Inhibitors of UDP-galactopyranose mutase

ABSTRACT

Compounds and salts thereof which inhibit microbial growth or attenuate the virulence of pathogenic microorganisms and which inhibit UDP-galactopyranose mutase (UGM). Compounds of the invention include triazolothiadiazines, particularly 3,6,7-substituted-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines, and 4-(1H-pyrrol-3-yl) thiazoles, particularly 4-(1,2,5-substituted-1H-pyrrol-3-yl)-2-substituted thiazoles, and salts thereof. Methods for inhibiting growth or attenuating virulence of microbial pathogens including mycobacterium, for example,  M. tuberculosis  and  M. smegmatis  and  Klebsiella , for example,  Klebsiella pneumoniae . Methods for inhibiting eukaryotic human and animal pathogens, and fungi and nematodes in particular. Methods for treatment of infections by prokaryotic and eukaryotic pathogens employing compounds of the invention.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of US provisional application62/007,355, filed Jun. 3, 2014. This provisional application isincorporated by reference herein in its entirety.

STATEMENT REGARDING GOVERNMENT SUPPORT

This invention was made with government support under AI063596 andGM059957 awarded by the National Institutes of Health. The governmenthas certain rights in the invention.

BACKGROUND OF THE INVENTION

Carbohydrates are the most ubiquitous class of biomolecules in nature,yet glycan diversity imparts unique sugar features that can be targetedin a species-specific manner. The monosaccharide galactofuranose (Galf)is found in cell surface glycoconjugates of many human pathogens.However, Galf is absent from the mammalian glycome [Richards, M. R. andT. L. Lowary, Chemistry and Biology of Galactofuranose-ContainingPolysaccharides. Chem Bio Chem, 2009. 10(12): p. 1920-1938], makingenzymes involved in metabolism of the sugar attractive targets fortreatment of human disease.

Galf contributes to virulence in infectious microbes such as Klebsiellapneumoniae (Kp) [Richards et al. 2009], Leishmania major, andAspergillus fumigatus [Tefsen, B., et al., Galactofuranose ineukaryotes: aspects of biosynthesis and functional impact. Glycobiology,2012. 22(4):456-469], as well as certain multicellular eukaryoticpathogens [Wesener, D. A., et al., UDP-galactopyranose mutase innematodes. Biochemistry, 2013. 52(25):4391-8]. Mycobacteriumtuberculosis, the causative agent of tuberculosis, harbors an essentialGalf polysaccharide known as galactan within its renown thick andhydrophobic cell wall complex [Pan, F., et al., Cell Wall CoreGalactofuran Synthesis Is Essential for Growth of Mycobacteria. JBacteriol, 2001. 183 (13):3991-3998]. Tuberculosis causes an estimated 2million deaths worldwide every year (WHO report 2014). With the rise ofmultidrug-resistant and extremely drug resistant M. tuberculosis (Mt),tuberculosis is becoming increasingly difficult to treat (WHO report2014). This underscores the need for new drug candidates in thepipeline.

Cell wall biosynthetic enzymes are targets of several first-lineantitubercular drugs, including isoniazid and ethambutol [Richards etal. 2009; Pan et al. 2001]. Uridine 5′-diphosphate (UDP)-galactopyranosemutase (UGM) generates the biological source of UDP-Galf, utilized bygalactofuranosyl transferases for construction of the mycobacterial cellwall galactan. UGM is a flavin-dependent protein that catalyzes ringcontraction of UDP-galactopyranose (UDP-Galp) to form UDP-Galf[Soltero-Higgin, M., et al., A unique catalytic mechanism forUDP-galactopyranose mutase. Nat Struct Mol Biol, 2004. 11(6): 539-543](FIG. 1), the five-membered ring isomer of nucleotide-linked galactose.UGM has been validated as a mycobacterial drug target [Dykhuizen, E. C.,et al., Inhibitors of UDP-galactopyranose mutase thwart mycobacterialgrowth. J Am Chem Soc, 2008. 130(21):6706-7; Borrelli, S., et al.,Antimycobacterial activity of UDP-galactopyranose mutase inhibitors.Int. J Antimicrob Agents, 2010. 36(4):364-8], and thus small moleculeUGM antagonists are highly sought after.

Most efforts to develop UGM inhibitors have focused on UDP-sugarsubstrate analogs. (Caravano, A.; Dohi, H.; Sinay, P.; Vincent, S. P.Chem.-Eur. J. 2006, 12, 3114-3123; Liautard, V.; Christina, A. E.;Desvergnes, V.; Martin, O. R. J. Org. Chem. 2006, 71, 7337-7345;Ghavami, A.; Chen, J. J. W.; Pinto, B. M. Carbohydr. Res. 2004, 339,401-407; Lee, R. E.; Smith, M. D.; Pickering, L.; Fleet, G. W. J.Tetrahedron Lett. 1999, 40:8689-8692; Liautard, V.; Desvergnes, V.;Martin, O. R. Org. Lett. 2006, 8, 1299-1302.) Simple sugar derivatives,including galactopyranose or galactofuranose analogs, bind weakly withaffinities in the millimolar range (Lee, R. E.; Smith, M. D.; Nash, R.J.; Griffiths, R. C.; McNeil, M.; Grewal, R. K.; Yan, W. X.; Besra, G.S.; Brennan, P. J.; Fleet, G. W. J. Tetrahedron Lett. 1997, 38,6733-6736; Veerapen, N.; Yuan, Y.; Sanders, D. A. R.; Pinto, B. M.Carbohydr. Res. 2004, 339, 2205-2217.) Inhibitors that incorporate theuridine portion of the substrate bind substantially better, withaffinities that approximate that of UDP-Galp (Kd=52 μM) (Itoh, K.;Huang, Z. S.; Liu, H. W. Org. Lett. 2007, 9, 879-882; Caravano, A.;Vincent, S. P.; Sinay, P. Chem. Commun. 2004, 1216-1217; Caravano, A.;Mengin-Lecreulx, D.; Brondello, J. M.; Vincent, S. P.; Sinay, P.Chem.-Eur. J. 2003, 9, 5888-5898; Pan, W. D.; Ansiaux, C.; Vincent, S.P. Tetrahedron Lett. 2007, 48, 4353-4356; Scherman, M. S.; Winans, K.A.; Stern, R. J.; Jones, V.; Bertozzi, C. R.; McNeil, M. R. Antimicrob.Agents Chemother. 2003, 47, 378-382.) These approaches have not yetafforded compounds that block mycobacterial growth.

Certain non-substrate based molecules have been identified as UMGligands. For example, certain nitrofuranylamides have been identified asinhibitors of UGM catalysis and mycobacterial growth. (Tangallapally, R.P.; Yendapally, R.; Lee, R. E.; Hevener, K.; Jones, V. C.; Lenaerts, A.J. M.; McNeil, M. R.; Wang, Y. H.; Franzblau, S.; Lee, R. E. J. Med.Chem. 2004, 47, 5276-5283.) Nevertheless, the UGM inhibition andantimycobacterial activity of these compounds were not correlated, sothey do not address the utility of inhibiting UGM.

Published International application WO 2005/007625 (Lee et al.), as wellas published U.S. application 20050222408, relate to certainheterocyclic amides with anti-tuberculosis activity. More specifically,these patent documents relate to compounds of formula:

wherein A is selected from the group consisting of oxygen, sulfur, andNR₁₅, where R₁₅ is selected from the group consisting of H, alkyl, aryl,substituted alkyl, and substituted aryl; B, D, and E are eachindependently selected from the group consisting of CH, nitrogen, sulfurand oxygen; R₁ is selected from the group consisting of nitro, halo,alkyl ester, arylsulfanyl, arylsulfinyl, arylsulfonyl and sulfonic acid;t is an integer from 1 to 3; and X is a substituted amide. These patentdocuments are incorporated by reference herein at least in part for thedefinitions of structural elements of the above formula.

A fluorescence polarization (FP) based assay has been developed thatallows detection of competitive UGM inhibitors [Soltero-Higgin, M., etal., Identification of inhibitors for UDP-galactopyranose mutase. J AmChem Soc, 2004. 126(34): p. 10532-3; Dykhuizen, E. C. and L. L.Kiessling, Potent ligands for prokaryotic UDP-galactopyranose mutasethat exploit an enzyme subsite. Org Lett, 2009. 11(1): p. 193-6]. Usingthis FP assay, several high-throughput screens (HTS) have beenconducted, endeavoring discovery of small molecule UGM ligands[Soltero-Higgin et al. 2004;, Carlson, E. E., J. F. May, and L. L.Kiessling, Chemical probes of UDP-galactopyranose mutase. Chem Biol,2006. 13(8): p. 825-37]. The screens culminated in fairly low hit rates,revealing the challenging nature of UGM as a target. Nonetheless,through HTS, one series of thiazolidinones (TZ) with considerableactivity towards UGM was discovered [Soltero-Higgin et al. 2004]. The TZseries was optimized through scaffold hopping to a 2-aminothiazole (AT)inhibitor core [Dykhuizen, et al., 2008]. The most potent AT displays anIC₅₀ of 7.2 μM and 37 μM against KpUGM and MtUGM, respectively[Dykhuizen, et al. 2008; Borrelli et al. 2010].

U.S. Pat. No. 8,273,778 issued Sept. 25, 2012 relates to inhibitors ofUDP-galactopyranose mutase having among others, 2-aminothiazolestructures. This issued patent is incorporated by reference herein inits entirety for descriptions of the UDP-galactopyranose mutaseinhibitors there as well as methods of assessing such inhibitors andmethods of application of such inhibitors.

While a number of small molecule inhibitors of UDP-galactopyranosemutase have been identified, there remains a need in the art foradditional inhibitors which exhibit effective inhibition ofmicroorganisms having UDP-galactopyranose mutase.

SUMMARY OF THE INVENTION

The invention provides compounds which inhibit microbial growth orattenuate the virulence of pathogenic microorganisms. In certainembodiments, compounds of the invention inhibit UDP-galactopyranosemutase (UGM) and have activity as inhibitors of microbial growth ofmicroorganisms which contain this enzyme and particularly thosemicroorganisms in which this enzyme is responsible for the incorporationof galactofuranose residues, particularly for uridine 5′-diphosphate(UDP) galactopyranose mutase. In certain embodiments, compounds of theinvention inhibit UDP-galactopyranose mutase (UGM) and have activity toattenuate virulence of pathogenic microorganisms which contain thisenzyme and particularly those microorganisms in which this enzyme isresponsible for the incorporation of galactofuranose residues.

More specifically, the inhibitors of UGM of this invention inhibitgrowth or attenuate virulence of microbial pathogens includingmycobacterium, for example, M. tuberculosis and M. smegmatis andKlebsiella, for example, Klebsiella pneumoniae. Additionally, UGMinhibitors of this invention can also inhibit UGM of certain eukaryotichuman and animal pathogens, those of fungi and nematodes in particular.Compounds of this invention are useful for treatment of infections byprokaryotic and eukaryotic pathogens. Compounds of this invention areuseful in human and veterinary treatment applications. Compounds of thisinvention are useful for the treatment of tuberculosis. Compounds ofthis invention are useful in combination therapy with other antibioticsfor the treatment of microbial infections, including tuberculosis.Compounds of this invention are useful for the treatment of multipledrug resistant microbial infections, including multiple drug resistanttuberculosis.

Compounds of the invention include triazolothiadiazines, particularly3,6,7-substituted-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines, and4-(1H-pyrrol-3-yl) thiazoles, particularly4-(1,2,5-substituted-1H-pyrrol-3-yl)-2-substituted thiazoles.

The invention provides triazolthidiazine compounds of formula I:

and salts thereof,

-   where:-   Y is —OR₃, is or —NH₂,-   R₃ is hydrogen, or an optionally substituted alkyl, cycloalkyl,    alkenyl, cycloalkenyl, heterocyclyl, aryl or heteroaryl group, and-   R₁ and R₂ are independently optionally substituted aryl or    heteroaryl groups having one or two rings or are alkyl groups    substituted with an optionally substituted aryl, aryloxy, heteroaryl    or heteroaryloxy group having one or two rings, particularly those    having two fused rings; and-   where optional substitution is substitution with one or more    halogen, nitro, cyano, isocyano, thiocyano, isothiocyano, hydroxyl,    C₁-C₆ alkyl, C₁-C₆ alkoxy, sulfonamide (—SO₂—N(R_(F))₂), azide,    sulfonyl (—SO₂—R_(F)), —COOR_(F), —COR_(F), —CON(R_(F))₂,    —N(R_(F))₂, and C₁-C₆ haloalkyl groups, including among others    trifluoromethyl, trichloromethyl and tribromomethyl groups, where    R_(F) is hydrogen or a C₁-C₆ alkyl group. Compounds of formula I are    useful for inhibition of mycobacteria or other microorganisms and/or    as intermediates in the synthesis of inhibition of mycobacteria.

In specific embodiments, Y is —OR₃. In specific embodiments, R₃ ishydrogen. In specific embodiments, R₃ is an unsubstituted alkyl grouphaving 1-3 carbon atoms. In specific embodiments, R₃ is an unsubstitutedcycloalkyl group having 3-8 carbon atoms. Alkyl and cycloalkyl groups ofR₃ can, in an embodiment, be optionally substituted with one or morehalogens. In specific embodiments, R₃ is an unsubstituted alkyl grouphaving 6-12 carbon atoms. In other specific embodiments, the R₁ and R₂groups both contain optionally substituted aryl or aryloxy groups,preferably optionally substituted phenyl or phenoxy (Ph—O—) groups. Inspecific embodiments, optional substitution is substitution with one ormore halogens, nitro, cyano, azide or haloalkyl groups. In specificembodiments, R₁ and R₂ are substituted phenyl groups or substitutedbenzyl groups. In specific embodiments, R₁ and R₂ are substitutedphenoxy groups or substituted benzyloxy groups. In specific embodiments,one of R₁ or R₂ is a para-iodo phenyl group or a para-iodobenzyl group.

The invention also provides 4-(1H-pyrrol-3-yl)thiazole compounds offormula II:

and pharmaceutically acceptable salts thereof,

-   where:-   Y is —OR₄, or —NH₂;-   p is 1, 2 or 3;-   R₄ is hydrogen, or an optionally substituted alkyl, cycloalkyl,    alkenyl, cycloalkenyl, heterocyclyl, aryl or heteroaryl group;-   each R₅ is independently hydrogen or an optionally substituted alkyl    group having 1-3 carbon atoms;-   R₁₀ is hydrogen or an —NR₆R₇ group, where:

R₆ is hydrogen, or optionally substituted alkyl, cycloalkyl, alkenyl,cycloalkenyl, heterocyclyl, aryl or heteroaryl groups; and

R₇ is hydrogen, or optionally substituted alkyl, cycloalkyl, alkenyl,cycloalkenyl, heterocyclyl, aryl or heteroaryl groups:

where optional substitution is substitution with one or more halogen,nitro, cyano, isocyano, thiocyano, isothiocyano, hydroxyl, C₁-C₆ alkyl,C₁-C₆ alkoxy, sulfonamide (—SO₂—N(R_(F))₂), azide, sulfonyl(—SO₂—R_(F)), —COOR_(F), —COR_(F) , —CON(R_(F))₂, —N(R_(F))₂, and C₁-C₆haloalkyl groups, including trifluoromethyl, trichloromethyl andtribromomethyl groups, where R_(F) is hydrogen or a C₁-C₆ alkyl group.Compounds of formula II are useful for inhibition of mycobacteria orother microorganisms and/or as intermediates in the synthesis ofinhibition of mycobacteria.

In specific embodiments of formula II, Y is —OR₄. In specificembodiments, R₄ is hydrogen. In specific embodiments, R₄ is an alkylgroup having 1-3 carbon atoms. In specific embodiments, R₄ is ancycloalkyl group having 3-8 carbon atoms. In specific embodiments, R₄ isan alkyl group having 6-12 carbon atoms. In specific embodiments, bothR₅ are methyl groups or one R₅ is hydrogen and the other is methyl

In other specific embodiments, one R₆ is hydrogen or a C₁-C₃ alkyl groupand the R₇ group is a substituted aryl group or an alkyl groupsubstituted with a substituted aryl group, preferably a substitutedphenyl groups. In specific embodiments, optional substitution issubstitution with one or more halogens, nitro, cyano, azide or haloalkylgroups. In specific embodiments, R₇ is a substituted benzyl group. Inspecific embodiments, R₇ is a 1-arylethy group, where the aryl group issubstituted. In specific embodiments, R₇ is a 1-phenylethyl group, wherethe phenyl group is substituted. In specific embodiments, R₇ contains ahalo-substituted phenyl group. In specific embodiments, R₇ contains ap-iodophenyl group.

In specific embodiments, compounds of the invention exhibit lowcytotoxicity with LD50 of 200 μM or less for human or animal cells. Inmore specific embodiments, compounds of the invention exhibit cytotoxityof LD50 of 100 or less for human or animal cells. Preferred compounds ofthe invention for treatment of a human or animal for a givenmicroorganism (bacterial, fungus, algae or nematode) exhibit LD50 forcells of the human or animal which is at least 4-fold or more preferably5-fold lower than the MIC of the compound for a given microorganism.

The invention provides pharmaceutically acceptable compositions whichcomprise one or more compounds of formula I or II and a pharmaceuticallyacceptable excipient. In specific embodiments, the excipient is otherthan water. In specific embodiments, the excipient is other than asolvent.

The invention provides methods for inhibiting UGM comprising contactingUGM with an amount of one or more of the compounds of formulas I or IIwhich is effective for inhibiting the enzyme.

The invention provides a method for inhibiting incorporation of Galfinto a microbial polysaccharide which comprises contacting themicroorganism or an environment containing the organism with an amountone or more compounds of formulas I or II effective for such inhibition.

The invention also provides methods for inhibiting the growth ofmycobacteria which comprises contacting the mycobacteria or anenvironment containing the mycobacteria with an amount of one or morecompounds of formulas I or II effective for such growth inhibition.

The invention also provides methods for treatment of a mycobacterialinfection which comprises administering to a human or non-human subjectin need of such treatment an amount of one or more compounds of formulaI or II effective for such treatment. In a specific embodiment, themycobacterial infection is tuberculosis.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a scheme of the isomerization reaction catalyzed by UGM.

FIGS. 2A and B are Log AUC enrichment plots of known UGM inhibitors vs.(FIG. 2A) property matched decoys or (FIG. 2B) the entire 4.7 millionlead-like ZINC library. The area under the curve for ligands from the ATscaffold or both AT+TZ scaffolds is indicated. The dashed linecorresponds to the performance of a random ranking of the library.

FIGS. 3A and B relate to in vitro analysis of predicted UGM inhibitors.FIG. 3A shows the structures (identified by number) of select moleculesfrom the top-ranking 0.01% of the docking library, which were tested forinhibition of KpUGM in vitro. Docking rank from the virtual screen isindicated in parentheses. FIG. 3B is a graph of KpUGM activity monitoredin the presence of predicted ligands via a discontinuous HPLC-basedassay. Due to solubility issues molecule 9 could not be tested at theseconcentrations.

FIGS. 4A-F relate to correlation of competitive KpUGM inhibition by 22and 30 with M. smegmatis cell-killing. FIGS. 4A and 4B are graphsshowing probe displacement in a competitive-binding FP assay, forcompound (22) and compound (30) with Kd values of 9.2 and 4.7 μM,respectively. Lineweaver-Burk analysis confirmed that 22 and 30 arecompetitive UGM inhibitors (FIGS. 4C and 4D, respectively). Bothcompounds display a Ki in the low micromolar range (Ki, 22=7.0 μM andKi, 30=1.1 μM), with 30 being about 5-fold more potent than 22 in vitro.The complementary nonlinear regression plot of KpUGM inhibition by 30 isshown (FIG. 4E) for comparison to double reciprocal analysis. FIG. 4F(left) is a graph of the alamar blue assay used to assess M. smegmatisviability in liquid culture. FIG. 4F (right) shows MICs were determinedafter 46 hours of growth in the presence of select UGM inhibitors. While22 showed no M. smegmatis growth repression at the testedconcentrations, 30 showed potent antimycobacterial activity, with a MICof 20 μM.

FIG. 5 is a composite of the results of multiple disk diffusion assaysshowing that UGM inhibitors display antimycobacterial activity in a diskdiffusion assay. Compounds 22, 27, 28, and 30 were tested forantibacterial activity against three bacterial strains. UGM is essentialfor viability of M. smegmatis, while E. coli (Gram-negative) and B.subtilis (Gram-positive) do not contain a UGM. The latter bacterialstrains were thus controls to evaluate inhibitor specificity andtoxicity. A DMSO vehicle control is shown, as well as UGM inhibitor,ED103. The radius of the growth inhibition zone (measured from outeredge of paper disk to the border of cell growth) is indicated in mm inthe upper left corner. The most potent new UGM inhibitor displays betterantimycobacterial activity and less off-target effects than ED103.

FIG. 6A-6B is a Table relating to hit-to-lead optimization of compound6. Analogs of 6 with varied R₁ and R₂ substituents (structures shown)were evaluated in SAR studies. KpUGM inhibition at 100 and 50 μM wasassessed for each compound.

FIG. 7A-7D shows structures of known UGM inhibitors used for dockingcalibration. The shown UGM inhibitors have been characterized inprevious studies, and were utilized as a training set for our virtualscreen.

FIG. 8 is a graph showing the effect of detergent on UGM inhibition bydocking molecules. Docking compounds were tested at 100 μM for KpUGMinhibition in the presence and absence of 0.025% Tween 80. Compounds 6and 10 appeared insensitive to detergent.

FIGS. 9A-9G include graphs (for the six compounds indicated) related todetection of colloid formers via DLS. DLS auto-correlation plots.Compounds 6, 10 and 22 (FIGS. 9A, 9B, 9D) show no sign of colloidalaggregation via DLS at 100 μM. Compounds 19, 24 and 30 (FIGS. 9C, 9E,9F) do form colloids at 100 μM. Compound 30, however, does not aggregateat 10 μM (FIG. 9G). Where available, the second curve in a graphrepresents a replicate of the experiment.

FIGS. 10A and 10B show graphs with characterization of docking forpredicted UGM inhibitors 6 and 10 by FP assay. Compounds 6 (FIG. 10A)and 10 (FIG. 10B) displayed Kd values of 43 and 6 μM, respectively.

FIGS. 11A-C illustrate analogs of compound 10 having improved UGMinhibition. Structures are shown in FIG. 11A. FIG. 11B is a graphassessing KpUGM inhibition in vitro where compound 14 showed increaseddose-dependent KpUGM inhibition in vitro. FIG. 11C is a graph assessingKd, where compound 14 also proved a slightly tighter binder (Kd=4.5 μM)(right) than the lead compound.

FIG. 12 illustrates Lineweaver Burk analysis of in vitro KpUGMinhibition by compound 6.

FIGS. 13 A and B are graphs illustrating FP analysis of selected firstgeneration compound 6 analogs. Compounds 19 (FIG. 13A) and 24 (FIG. 13B)displayed Kd values of 15 μM and 9.2 μM, respectively.

FIG. 14 is a graph illustrating that exemplary compound 30 is selectivefor KpUGM over MtUGM and CdUGM.

FIG. 15 is a graph showing non-specific MDH inhibition by compound 30.Compound 30 shows non-specific inhibition of MDH with IC50=55.7 μM. Thisinhibition is reversible by the addition of detergent, a hallmark ofcolloidal aggregation.

FIG. 16 is a graph showing binding of compound 30 to KpUGM wasinsensitive to detergent. The FP assay was used to show that the Kd of30 is unaffected by the presence of detergent. This indicates that KpUGMbinding is specific, and not an artifact of small molecule aggregation.

FIG. 17 illustrates cytotoxicity of 30 with HEK293 cells. Compound 30toxicity to human cells is comparable to the previously described UGMinhibitor ED103 with and LD50˜100 μM. The parent compound, 6, displaysno significant cellular toxicity.

DETAILED DESCRIPTION OF THE INVENTION

This invention is at least in part based on structure-based virtualscreening for inhibitors of UDP-galactopyranose mutase. Morespecifically, small molecule UGM ligands were predicted in silico, andtop-ranking molecules were tested for activity in enzyme assays. In thisway, a series of competitive UGM inhibitors that not only inhibit UGM invitro but also possess antimycobacterial activity have been identified.

In silico structure-based virtual screening [Shoichet, B. K., Virtualscreening of chemical libraries. Nature, 2004. 432(7019): p. 862-5] is acomputational approach complementary to empirical HTS for identificationof small molecule binders of a specific protein target [Ferreira, R. S.,et al., Complementarity between a docking and a high-throughput screenin discovering new cruzain inhibitors. J Med Chem, 2010. 53(13): p.4891-905]. Virtual screening has been shown to have better hit-ratesthan HTS as well as aid in discovery of more chemically novel leads[Babaoglu, K., et al., Comprehensive mechanistic analysis of hits fromhigh-throughput and docking screens against beta-lactamase. J Med Chem,2008. 51(8): p. 2502-11]. This method is highly cost effective andallows screening of a broad scope of small molecules, many of which arenot part of established HTS screening decks. Virtual screening hits areoften weaker binders compared to HTS. However, this can be advantageous,as HTS is at times overly stringent, and thus may overlook weakerbinding ligands that could yield potent, specific inhibitors after leadoptimization and structure-activity relationship (SAR) analyses.

In the present work, the DOCK program [Lorber, D. M. and B. K. Shoichet,Hierarchical docking of databases of multiple ligand conformations. CurrTop Med Chem, 2005. 5(8): p. 739-49; Mysinger, M. M. and B. K. Shoichet,Rapid context-dependent ligand desolvation in molecular docking. J ChemInf Model, 2010. 50(9): p. 1561-73] was used to virtually screen adatabase of 4.7 million commercially available compounds for competitiveUGM ligands. Through exploring the SAR of a weak binding hit from thescreen, potent UGM inhibitors with marked antimycobacterial activitywere identified.

The compounds identified contain either a bicyclic triazolo thiadiazinecore with diversified aromatic substituents (Formula I) or a1H-pyrrol-3-ylthiazole structure with various substituents (Formula II).

Additionally, the structure of the first UGM-small molecule complex hasbeen identified. This structure can guide further optimization of thisinhibitor series.

The inhibitors of this invention are useful for inhibition of growth ofmicroorganisms, including bacteria and eukaryotic organisms, such asprotozoa and nematodes and the treatment of diseases caused by suchorganisms. In a specific embodiment, the inhibitors of this inventionare useful for inhibition of growth of mycobacteria, and for thetreatment of mycobacterial disease. Further the inhibitors of thisinvention are useful as tools to probe the role of UGM in biologicalsystems. The invention also provided compounds which can be employed asintermediates in the synthesis of additional UGM inhibitors having thestructures of formula I and II.

In specific embodiments of formula I, R₁is selected from hydrogen,fur-2-yl, p-F-phenyl, p-F-benzyl, thien-2-yl, 1-methylfur-3-yl,p-Cl-phenoxy-CH₂-, o-methoxyphenyl, p-F-phenyl, p-F-benzyl, p-Br-benzyl,p-Br-phenyl, p-Cl-phenyl, p-Cl-benzyl.

In specific embodiments of formula I, R₂ is selected from p-F-phenyl,p-F-benzyl, p-F-phenyl, p-Cl-benzyl p-Cl-phenyl, p-Br-benzyl,p-Br-phenyl, thien-2-yl, phenyl, or p-methylphenyl.

In specific embodiments of formula I, R₁ is selected from hydrogen,fur-2-yl, p-F-phenyl, p-F-benzyl, thien-2-yl, 1-methylfur-3-yl,p-Cl-phenoxy-CH₂-, o-methoxyphenyl, p-F-phenyl, p-F-benzyl, p-Br-benzyl,p-Br-phenyl, p-Cl-phenyl, p-Cl-benzyl and R₂ is selected fromp-F-phenyl, p-F-benzyl, p-F-phenyl, p-Cl-benzyl p-Cl-phenyl,p-Br-benzyl, p-Br-phenyl, thien-2-yl, phenyl, or p-methylphenyl.

In specific embodiments of formula I, R₁ is selected from hydrogen,fur-2-yl, p-F-phenyl, p-F-benzyl, thien-2-yl, 1-methylfur-3-yl,p-Cl-phenoxy-CH₂-, o-methoxyphenyl, p-F-phenyl, p-F-benzyl, p-Br-benzyl,p-Br-phenyl, p-Cl-phenyl, p-Cl-benzyl and R₂ is selected fromp-F-phenyl, p-F-benzyl, p-F-phenyl, p-Cl-benzyl p-Cl-phenyl,p-Br-benzyl, p-Br-phenyl, thien-2-yl, phenyl, or p-methylphenyl with theexception that the compound is a compound other than compound 6 or acompound other than compounds 16-31.

In specific embodiments of formula I, R₁ is p-I-phenyl.

In specific embodiments of formula I, R₁ is p-I-benzyl.

In specific embodiments of formula I, R₂ is selected from p-F-phenyl,p-F-benzyl, p-F-phenyl, p-Cl-benzyl p-Cl-phenyl, p-Br-benzyl,p-Br-phenyl, thien-2-yl, phenyl, or p-methylphenyl.

In specific embodiments of formula I, R₁ is p-Br-phenyl-; p-Cl-phenyl;p-Cl-benzyl; p-I-phenyl; p-I-benzyl; p-Br-phenoxy-CH₂—;p-I-phenoxy-CH₂—; or p-F-phenoxy-CH₂—.

In specific embodiments of formula I, R₂ is p-halo-benzyl.

In specific embodiments of formula I, R₂ is p-Br-benzyl.

In specific embodiments of formula I, R₂ is p-I-benzyl.

In specific embodiments of formula I, R₂ is p-I-phenyl.

In specific embodiments of formula I:

R₂ is 2-thienyl and R₁ is p-Br-benzyl, p-Cl-benzyl, p-I-benzyl,p-halophenyl, p-methylphenyl or phenyl;

R₂ is p-Cl-phenyl and R₁ is p-F-benzyl, p-Cl-phenyl, p-Cl-benzyl,p-Cl-phenoxy-CH₂—, p-Br-phenyl, p-I-phenyl or p-I-benzyl;

R₂ is p-methylphenyl and R₁ is p-Br-phenyl, p-Br-benzyl, p-Cl-phenyl,p-Cl-benzyl, p-I-phenyl or p-I-benzyl;

R₂ is phenyl and R₁ is p-Br-phenyl, p-Br-benzyl, p-Cl-phenyl,p-Cl-benzyl, p-I-phenyl or p-I-benzyl;

R₂ is p-F-phenyl and R₁ is p-F-phenyl, p-F-benzyl, p-Cl-phenoxy-CH₂—, orthien-2-yl;

R₂ is o-methoxyphenyl and R₁ is p-F-phenyl, p-F-benzyl,p-Cl-phenoxy-CH₂, thien-2-yl, p-Br-phenyl, p-Br-benzyl, p-I-phenyl,p-I-benzyl or p-C-benzyl.

R₁ is p-F-phenyl and R₂ is p-F-phenyl, p-F-benzyl, p-Cl-benzyl,thien-2-yl, p-I-phenyl, p-I-benzyl, p-Br-phenyl, or p-Br-benzyl;

R₁ is p-F-benzyl and R₂ is p-Cl-phenyl, p-Cl-benzyl, p-I-phenyl,p-I-benzyl, p-Br-phenyl, or p-Br-benzyl;

R₁ is p-Br-benzyl and R₂ is thien-2-yl, p-Cl-benzyl, p-Br-phenyl,p-Br-benzyl, p-I-phenyl, or p-I-benzyl;

R₁ is fur-2-yl and R₂ is p-Br-phenyl;

R₁ is thien-2-yl and R₂ is p-F-phenyl, p-Br-phenyl, or p-I-phenyl; or

R₁ is p-Cl-phenoxy-CH₂— and R₂ is p-F-phenyl, p-F-benzyl, p-Cl-phenyl,p-Cl benzyl, p-Br-phenyl, p-Br-benzyl, p-I-phenyl, or p-I-benzyl.

In specific embodiments, one of R₁ or R₂ is a dichloro-, difluoro- ordibromophenyl.

In specific embodiments, one of R₁ or R₂ is a o, p-dichloro-, o,p-difluoro- or o, p-dibromophenyl.

In specific embodiments, one of R₁ or R₂ is a m, m-dichloro-, m,m-difluoro- or m, m-dibromophenyl.

In specific embodiments, the invention provides compounds of formula IA:

and salts thereof

-   where:-   Y is as defined for formula I and preferably Y is —OR₃ and more    preferably R₃ is hydrogen;-   n and m are 0 or 1, including both n and m=0, n=0 and m=1 or n=1 and    m=0;-   A and B are optionally substituted phenyl rings or are    heteroaromatic rings, including thien-2-yl, fur-2-yl and fur-3-yl.-   In specific embodiments, A and B are both optionally substituted    phenyl rings. In specific embodiments at least one of A and B is    substituted. In specific embodiments, at least one of A and B is    substituted with one or more halogens. In specific embodiments, at    least one of A and B is substituted with two or three halogens. In    specific embodiments, one of A or B is a heteroaryl group.

In specific embodiments, the invention provides compounds of formula IB:

and salts thereof

-   where:-   Y is as defined for formula I and preferably Y is —OR₃ and more    preferably R₃ is hydrogen;-   n and m are 0 or 1, including both n and m=0, n=0 and m=1 or n=1 and    m=0;-   R_(C) and R_(B) represent optional substitution on the indicated    phenyl rings, where preferred optional substitution is as defined as    formula I above. In specific embodiments, optional substitution is    substitution with one to five halogens, one or two nitro, cyano,    isocyano, or thiocyano groups or one to three C₁-C₃ alkoxy group    (particularly methoxy groups), or one or two C₁-C₃ alkyl groups    (particularly methyl groups).

In specific embodiments of formula IB:

-   R_(B) is substitution by five halogens on the B ring;-   R_(B) is substitution by five fluorines on the B ring;-   R_(B) is substitution by three halogens on the B ring;-   R_(B) is substitution by three chlorines on the B ring;-   R_(B) is substitution by three bromines on the B ring;-   R_(B) is substitution by three fluorines on the B ring;-   R_(B) is substitution by three iodines on the B ring;-   R_(B) is substitution by halogens at carbons 2, 3 and 4 on the B    ring (see formula IB);-   R_(B) is substitution by chlorines at carbons 2, 3 and 4 on the B    ring;-   R_(B) is substitution by fluorines at carbons 2, 3 and 4 on the B    ring;-   R_(B) is substitution by bromines at carbons 2, 3 and 4 on the B    ring;-   R_(B) is substitution by iodines at carbons 2, 3 and 4 on the B    ring;-   R_(B) is substitution by halogens at carbons 1, 2 and 3 on the B    ring;-   R_(B) is substitution by chlorines at carbons 2, 3 and 4 on the B    ring;-   R_(B) is substitution by two halogens on the B ring;-   R_(B) is substitution by two chlorines on the B ring;-   R_(B) is substitution by two bromines on the B ring;-   R_(B) is substitution by two iodines on the B ring;-   R_(B) is substitution by two fluorines on the B ring;-   R_(B) is substitution by halogens at carbons 2 and 4 on the B ring;-   R_(B) is substitution by fluorines at carbons 2 and 4 on the B ring;-   R_(B) is substitution by chlorines at carbons 2 and 4 on the B ring;-   R_(B) is substitution by bromines at carbons 2 and 4 on the B ring;-   R_(B) is substitution by iodines at carbons 2 and 4 on the B ring;-   R_(B) is substitution by halogens at carbons 1 and 3 on the B ring;-   R_(B) is substitution by fluorines at carbons 1 and 3 on the B ring;-   R_(B) is substitution by chlorines at carbons 1 and 3 on the B ring;-   R_(B) is substitution by bromines at carbons 1 and 3 on the B ring;-   R_(B) is substitution by iodines at carbons 1 and 3 on the B ring;-   R_(B) is substitution by halogens at carbons 2 and 3 on the B ring;-   R_(B) is substitution by fluorines at carbons 2 and 3 on the B ring;-   R_(B) is substitution by chlorines at carbons 2 and 3 on the B ring;-   R_(B) is substitution by bromines at carbons 2 and 3 on the B ring;-   R_(B) is substitution by iodines at carbons 2 and 3 on the B ring;-   R_(B) is substitution by one halogen on the B ring;-   R_(B) is substitution by one fluorine on the B ring;-   R_(B) is substitution by one chlorine on the B ring;-   R_(B) is substitution by one bromine on the B ring;-   R_(B) is substitution by one iodine on the B ring;-   R_(B) is substitution by one halogen on carbon 3 of the B ring;-   R_(B) is substitution by one fluorine on carbon 3 of the B ring;-   R_(B) is substitution by one chlorine on carbon 3 of the B ring;-   R_(B) is substitution by one chlorine on carbon 2 of the B ring;-   R_(B) is substitution by one chlorine on carbon 1 of the B ring;-   R_(B) is substitution by one bromine on carbon 3 of the B ring;-   R_(B) is substitution by one iodine on carbon 3 of the B ring;-   R_(B) is substitution by one nitro group on the B ring;-   R_(B) is substitution by one nitro group on carbon 2 of the B ring;-   R_(B) is substitution by one nitro group on carbon 3 of the B ring;-   R_(B) is substitution by one hydroxyl group on the B ring;-   R_(B) is substitution by one hydroxyl group on carbon 3 of the B    ring;-   R_(B) is substitution by one methoxy group on the B ring;-   R_(B) is substitution by one methoxy group on carbon 3 of the B    ring;-   R_(B) is substitution by one cyano group on the B ring;-   R_(B) is substitution by one cyano group on carbon 3 of the B ring;-   R_(B) is substitution by a C1-C6 alkyl group at carbon 3 of the B    ring;-   R_(B) is substitution by a nitro group at carbon 2 and a halogen at    carbon 3 of the B ring;-   R_(B) is substitution by a nitro group at carbon 2 and a chlorine at    carbon 3 of the B ring;-   R_(B) is substitution by a C1-C3 alkyl group at carbon 1 and a    halogen at carbon 3 of the B ring;-   R_(B) is substitution by a C1-C3 alkyl group at carbon 1 and a    hydroxy at carbon 3 of the B ring; or-   R_(B) is substitution including two different substituents on the B    ring.

The various embodiments of B ring substitution above can be combinedwith the various embodiments of C ring substitution below.

In specific embodiments of formula IB:

-   R_(C) is substitution by five halogens on the C ring;-   R_(C) is substitution by five fluorines on the C ring;-   R_(C) is substitution by three halogens on the C ring;-   R_(C) is substitution by three chlorines on the C ring;-   R_(C) is substitution by three bromines on the C ring;-   R_(C) is substitution by three fluorines on the C ring;-   R_(C) is substitution by three iodines on the C ring;-   R_(C) is substitution by halogens at carbons 2, 3 and 4 on the C    ring;-   R_(C) is substitution by chlorines at carbons 2, 3 and 4 on the C    ring;-   R_(C) is substitution by fluorines at carbons 2, 3 and 4 on the C    ring;-   R_(C) is substitution by bromines at carbons 2, 3 and 4 on the C    ring;-   R_(C) is substitution by iodines at carbons 2, 3 and 4 on the C    ring;-   R_(C) is substitution by two halogens on the C ring;-   R_(C) is substitution by two chlorines on the C ring;-   R_(C) is substitution by two bromines on the C ring;-   R_(C) is substitution by two iodines on the C ring;-   R_(C) is substitution by two fluorines on the C ring;-   R_(C) is substitution by halogens at carbons 2 and 4 on the C ring;-   R_(C) is substitution by fluorines at carbons 2 and 4 on the C ring;-   R_(C) is substitution by chlorines at carbons 2 and 4 on the C ring;-   R_(C) is substitution by bromines at carbons 2 and 4 on the C ring;-   R_(C) is substitution by iodines at carbons 2 and 4 on the C ring;-   R_(C) is substitution by halogens at carbons 1 and 3 on the C ring;-   R_(C) is substitution by fluorines at carbons 1 and 3 on the C ring;-   R_(C) is substitution by chlorines at carbons 1 and 3 on the C ring;-   R_(C) is substitution by bromines at carbons 1 and 3 on the C ring;-   R_(C) is substitution by iodines at carbons 1 and 3 on the C ring;-   R_(C) is substitution by halogens at carbons 2 and 3 on the C ring;-   R_(C) is substitution by fluorines at carbons 2 and 3 on the C ring;-   R_(C) is substitution by chlorines at carbons 2 and 3 on the C ring;-   R_(C) is substitution by bromines at carbons 2 and 3 on the C ring;-   R_(C) is substitution by iodines at carbons 2 and 3 on the C ring;-   R_(C) is substitution by one halogen on the C ring;-   R_(C) is substitution by one fluorine on the C ring;-   R_(C) is substitution by one chlorine on the C ring;-   R_(C) is substitution by one bromine on the C ring;-   R_(C) is substitution by one iodine on the C ring;-   R_(C) is substitution by one halogen on carbon 3 of the C ring;-   R_(c) is substitution by one fluorine on carbon 3 of the C ring;-   R_(C) is substitution by one chlorine on carbon 3 of the C ring;-   R_(C) is substitution by one bromine on carbon 3 of the C ring;-   R_(C) is substitution by one iodine on carbon 3 of the C ring;-   R_(C) is substitution by one nitro group on the C ring;-   R_(C) is substitution by one nitro group on carbon 2 of the C ring;-   R_(C) is substitution by one nitro group on carbon 3 of the C ring;-   R_(C) is substitution by one hydroxyl group on the C ring;-   R_(C) is substitution by one hydroxyl group on carbon 3 of the C    ring;-   R_(C) is substitution by one cyano group on the C ring; or-   R_(C) is substitution by one cyano group on carbon 3 of the C ring;

In specific embodiments, the invention provides compounds of formulaIIA:

and salts thereof

-   where: Y, p, R₅ R₇ and R₈ are as defined above.

In specific embodiments, the invention provides compounds of formula IIother than compounds 10, 14 and 15.

In specific embodiments, R₆ is hydrogen or methyl. In specificembodiments, R₇ is an optionally substituted phenyl, an optionallysubstituted benzyl or a 1-phenylethyl group, where the phenyl group isoptionally substituted. In specific embodiments, R₇ contains asubstituted phenyl group. In specific embodiments, R₇ contains ap-halogen substituted phenyl group. In specific embodiments, the phenylgroup of R₇ is substituted with 1-5 halogens, including 1-3 chlorines,1-3, fluorines , 1-5 fluorines, 1-2 bromines or 1-2 iodines. In specificembodiments, the phenyl group of R₇ is substituted with one or twomethyl or methoxy groups. In specific embodiments, the phenyl group ofR₇ is substituted with one or two nitro, azide, cyano, isocyano orthiocyano groups. In specific embodiments, R₇ is an optionallysubstituted benzyl group. In specific embodiments, R₇ is a substitutedbenzyl group. In specific embodiments, R₇ is a p-halogen substitutedbenzyl group. In specific embodiments, the benzyl group of R₇ issubstituted with 1-5 halogens, including 1-3 chlorines, 1-3, fluorines,1-5 fluorines, 1-2 bromines or 1-2 iodines on the phenyl ring. Inspecific embodiments, the benzyl group of R₇ is substituted with one ortwo methyl or methoxy groups on the phenyl ring. In specificembodiments, the benzyl group of R₇ is substituted with one or twonitro, azide, cyano, isocyano or thiocyano groups on the phenyl ring. Inspecific embodiments, R₇ is an optionally substituted phenethyl group.In specific embodiments, R₇ is a substituted phenethyl group. Inspecific embodiments, R₇ is a p-halogen substituted phenethyl group. Inspecific embodiments, the phenethyl group of R₇ is substituted with 1-5halogens, including 1-3 chlorines, 1-3, fluorines , 1-5 fluorines, 1-2bromines or 1-2 iodines on the phenyl ring. In specific embodiments, thephenethyl group of R₇ is substituted with one or two methyl or methoxygroups on the phenyl ring. In specific embodiments, the benzyl group ofR₇ is substituted with one or two nitro, azide, cyano, isocyano orthiocyano groups on the phenyl ring.

Certain compounds useful in the methods of this invention are availablefrom commercial sources. Novel compounds of the invention can beprepared by one of ordinary skill in the art employing synthetic methodsthat are well-known in the art or by routine adaptation of such methodsfrom starting material and reagents that are available commercially orreadily prepared by well-known methods. Schemes 1 and 2 illustrateexemplary synthetic schemes by which compounds of formulas I and II canbe prepared from available starting materials by known methods. Methodsuseful in the preparation of compounds of the invention of formulas Iand II can be found in the following references each of which isincorporated by reference herein in its entirety for the syntheticmethods therein:

Dhindsa, G. S.; Vaid, R. K. (1986) Synthesis and mass spectral studiesof some3-alkyl-6-aryl-7-carbethoxy/carboxy-methyl-s-triazolo[3,4-b][1,3,4]thiadiazinesIndian Journal of Chemistry, Section B: Organic Chemistry IncludingMedicinal Chemistry 25B(3), 283-7; Mazzone, G.; Bonina, F et al. (1989)Carboxymethyl- and carboxy-derivatives of 7H- and5H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazine: synthesis and biologicalevaluation Farmaco 44(10), 933-44.; Jakhar, A., Makrandi, J. K. (2012)Molecular iodine mediated one step synthesis and antibacterialproperties of some3-aryl-6-(6-substituted-4-methylcinnolin-3-yl)-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazinesIndian Journal of Chemistry, Section B: Organic Chemistry IncludingMedicinal Chemistry 51B(1), 313-317; Aytac, S. P; Tozkoparan, B, Kaynak,et al. (2009) Synthesis of 3,6-disubstituted7H-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines as novelanalgesic/anti-inflammatory compounds European Journal of MedicinalChemistry 44(11), 4528-4538; WO 2009089027 A20090716; El-Serwy W. S. etal. (2013) Res. Chem. Intermed. 39:2543-2554; and Vovk, M. et al. (2010)Molecules 15:997-1006

The invention provides a method for inhibiting UGM in vitro or in vivoby contacting a biological composition comprising an active UGM with anamount of one or more of the compounds of any of the formulas hereineffective for inhibiting UGM. In a specific embodiment, the inhibitionof UGM is in vivo in a prokaryote. In a specific embodiment, theinhibition of UGM is in vivo in a eukaryote. In a specific embodiment,the inhibition of UGM is in vivo in a nematode.

The invention also provides a method for inhibiting the growth of amicroorganism containing UGM by contacting the microorganism with anamount of one or more of the compounds of any of the formulas hereineffective for inhibiting the growth of the microorganism. In a specificembodiment, the microorganism is a human or veterinary pathogen. In aspecific embodiment, the microorganism is a bacterium. In anotherembodiment, the microorganism is of the genus Mycobacterium. In morespecific embodiments, the microorganism is Mycobacterium tuberculosis orMycobacterium smegmatis. In another embodiment, the microorganism is ofthe genus Klebsiella, including Klebsiella pneumoniae. In otherembodiments, the microorganism is a prokaryote or a eukaryote.

The invention also provides a method for attenuating the virulence of amicroorganism containing UGM by contacting the microorganism with anamount of one or more of the compounds of any of the formulas hereineffective for attenuating virulence of the microorganism. In a specificembodiment, the microorganism is a human or veterinary pathogen. In aspecific embodiment, the microorganism is a bacterium. In anotherembodiment, the microorganism is of the genus Mycobacterium. In morespecific embodiments, the microorganism is Mycobacterium tuberculosis orMycobacterium smegmatis. In another embodiment, the microorganism is ofthe genus Klebsiella, including Klebsiella pneumoniae. In otherembodiments, the microorganism is a prokaryote or a eukaryote.

The invention also provides a method for inhibiting the growth of amicroorganism containing UGM by contacting the microorganism with anamount of one or more of the compounds of any of the formulas hereineffective for inhibiting UGM. In a specific embodiment, themicroorganism is a human or veterinary pathogen. In a specificembodiment, the microorganism is a bacterium. In another embodiment, themicroorganism is of the genus Mycobacterium. In more specificembodiments, the microorganism is Mycobacterium tuberculosis orMycobacterium smegmatis. In another embodiment, the microorganism is ofthe genus Klebsiella, including Klebsiella pneumoniae. In otherembodiments, the microorganism is a prokaryote or a eukaryote.

The invention further provides a method of treating a human, a non-humanmammal or a non-human animal individual having or believed to have aninfection of a microorganism containing UGM by administering to theindividual an amount of one or more compounds of any of the formulasherein effective for inhibiting the growth of the microorganism. Inspecific embodiments, the microorganism is a bacterium or amycobacterium. In specific embodiments, the mycobacterial infection istuberculosis. In specific embodiments, the microorganism is of the genusMycobacterium or Klebsiella. In additional embodiments, themicroorganism is Mycobacterium tuberculosis, Mycobacterium smegmatis orKlebsiella pneumoniae. The pathogenic microorganism can be a prokaryoteor a eukaryote.

The invention additionally provides a method for treating a human, anon-human mammal or a non-human animal individual having or believed tohave an infection of a microorganism containing UGM by administering aneffective amount of a compound of this invention of any of the formulasherein, in combination with an antibiotic or antiparasitic agentappropriate for treatment of the infection. Compounds of this inventioncan enhance the effectiveness of art-known antibiotics and are useful incombination therapy in addition to such antibiotics. The compounds ofthe present invention can, for example, be employed in combinationtherapy with antibiotics, such as ethambutol, isoniazid, rifampicin, andpyrazinamide. Such combination therapy is particularly useful in thetreatment of mycobacterial infections.

The invention further provides a method of treating a human, a non-humanmammal or a non-human animal individual having or believed to have aninfection of a parasitic pathogen containing UGM by administering to theindividual an amount of one or more compounds of any of the formulasherein effective for inhibiting the growth of the parasitic pathogen. Inspecific embodiments, the parasitic pathogen is a protozoan or anematode. In a related embodiment, the treatment method includesadministering an effective amount of a compound of this invention of anyof the formulas herein, in combination with antiparasitic agentappropriate for treatment of the infection. The compounds of the presentinvention can, for example, be employed in combination therapy withantiparasitic agent, particularly anthelminthic agents, such asdiethylcarbamazine, teracyclies, rifampicin, chloramphenicol,alendazole, mebendazole, levamisole, pyrantel and ivermectic orcombinations of two or more thereof. Such combination therapy isparticularly useful in the treatment of nematode infections.

The invention additional provides a medicament comprising one or morecompounds of the formulas herein effective for inhibiting the growth ofa microorganism, including a eukaryotic parasite, or effective forattenuating the virulence of a microorganism, including a eukaryoticparasite, which contains UGM. The invention additional provides amedicament comprising one or more compounds of any of the formulasherein effective for inhibiting UGM. In specific embodiments, themicroorganism is a bacterium or a mycobacterium. In specificembodiments, the microorganism is of the genus Mycobacterium orKlebsiella. In additional embodiments, the microorganism isMycobacterium tuberculosis, Mycobacterium smegmatis or Klebsiellapneumoniae. In additional embodiments, the invention provides amedicament comprising one or more compounds of the formulas hereineffective for inhibiting the growth of a protozoan or effective forattenuating the virulence of a protozoan which contains UGM. Theinvention additional provides a medicament comprising one or morecompounds of any of the formulas herein effective for inhibiting UGM ofa protzoan. In specific embodiments, the protozoan are among others.Plasmodium, Trypanosomes and Leishmania. In additional embodiments, theinvention provides a medicament comprising one or more compounds of theformulas herein effective for inhibiting the growth of a nematode oreffective for attenuating the virulence of a nematode which containsUGM. The invention additional provides a medicament comprising one ormore compounds of any of the formulas herein effective for inhibitingUGM of a nematode. Nematode include among others, Ancylostoma, Necator,Ascaris, Strongyloides, Trichinella, Capillaria, Toxocara, Toxascaris,Trichuris, Enterobius, Onchocerca, Brugia, Wuchereria, or Dracunculus.

The invention also provides a method of making a medicament for treatingan individual (human, mammal or animal) having a bacterial ormycobacterial infection. In specific embodiments, the mycobacterialinfection is tuberculosis. In specific embodiments, the microorganism isof the genus Mycobacterium or Klebsiella. In additional embodiments, themicroorganism is Mycobacterium tuberculosis, Mycobacterium smegmatis orKlebsiella pneumoniae. In a specific embodiment, the method of making amedicament includes the step of combining an amount of a compound of anyof the formulas herein with a pharmaceutically effective carrier. In aspecific embodiment, the medicament is in a dosage form appropriate fororal administration, topical administration or administration byinjection.

In specific embodiments, the invention also provides compounds of any ofthe formulas herein which inhibit the growth of a microorganism havingUGM which exhibit a dissociation constant K for the UGM enzyme of 100 μMor less. In another embodiment, the compound exhibits a dissociationconstant K for the UGM enzyme of 50 μM or less. In another embodiment,the compound exhibits a dissociation constant K for the UGM enzyme of 25μM or less. In another embodiment, the compound exhibits a dissociationconstant K for the UGM enzyme of 10 μM or less. In further embodiments,the microorganism is a Mycobacterium, particularly Mycobacteriumtuberculosis. In additional embodiments the microorganism is of thegenus Klebsiella.

In specific embodiments, the invention provides compound of any formulasherein which exhibit Kd (μM) on UGM_(myco) of 100 or less. In otherembodiments, the invention provides compound of any formulas hereinwhich exhibit Kd (μM) on UGM_(myco) of 80 or less. In other embodiments,the invention provides compound of any formulas herein which exhibit Kd(μM) on UGM_(myco) of 60 or less. In other embodiments, the inventionprovides compounds of any formulas herein which exhibits exhibit Kd (μM)as measured by the fluorescence polarization assay on the UGM isoformfrom M. tuberculosis of 25 or less.

In specific embodiments, the invention provides compounds of anyformulas herein which exhibit Kd (μM) as measured by the fluorescencepolarization assay on the UGM isoform from K. pneumoniae of 80 or less.In other embodiments, the invention provides compounds of any formulasherein which exhibit Kd (μM) as measured by the fluorescencepolarization assay on the UGM isoform from K pneumoniae of 60 or less.In other embodiments, the invention provides compounds of any formulasherein which exhibit Kd (μM) as measured by the fluorescencepolarization assay on the UGM isoform from K. pneumoniae of 25 or less.

The invention further provides a method for inhibiting UGM in vitro orin vivo by contacting a biological composition comprising an active UGMwith an amount of one or more of the compounds of any of the formulasherein effective for inhibiting UGM. In a specific embodiment, theinhibition of UGM is in vivo in a prokaryote. In a specific embodiment,the inhibition of UGM is in vivo in a eukaryote.

Compounds of the invention are useful for inhibiting the growth of amicroorganism containing UGM which is the enzyme responsible for theconversion of UDP-galactopyranose to UDP-galactofuranose. UGM isexpected to be present in microorganisms in which galactofuranose (Galf)residues are present, for example in cell walls. Galactofuranose (Galf)residues are present in many pathogenic microorganisms (Pedersen, L. L.;Turco, S. J. Cell. Mol. Life Sci. 2003, 60, 259-266.) The gene encodingUGM is essential for mycobacterial viability (Pan, F.; Jackson, M.; Ma,Y. F.; McNeil, M. J. Bacteriol. 2001, 183, 3991-3998) suggesting thatGalf-containing glycoconjugates are necessary components of themycobacterial cell wall. Compounds of the invention are useful forinhibiting the growth of microorganisms containing galactofuranoseresidues, particularly those having such residues in the cell wall andmore particularly pathogenic microorganisms containing galactofuranoseresidues.

Compounds of the invention are useful for inhibition of growth ofmicroorganisms of the genus Mycobacterium, particularly including M.tuberculosis and M. smegmatis. Compounds of the invention can also beemployed to inhibit the growth of Mycobacterium leprae, Mycobacteriumbovis, Mycobacterium africanum, Mycobacterium canetti, and Mycobacteriummicroti.

Compounds of the invention are useful for inhibition of the growth ofGram-negative bacteria and particularly those of the genus Klebsiellaand particularly K. Pneumoniae. The compounds of the invention can alsobe employed to inhibit the growth of Klebsiella ozaenae, Klebsiellarhinoscleromatis, Klebsiella oxytoca, Klebsiella planticola, Klebsiellaterrigena, and Klebsiella ornithinolytica. Klebsiellae are importantpathogens in nosocomial infections. The compounds of the invention areuseful for the treatment of nosocomial infections.

Compounds of the invention are useful for inhibition of the growth of orfor attenuation of the virulence of eukaryotic pathogens, includingyeast, fungi, protozoa and nematodes. The compounds of the invention areuseful for inhibiting the growth or attenuating the virulence of, forexample, pathogenic Aspergillus, in particular Aspergillus fumagatus.

The term “microorganism” is used broadly herein to refer to organismstoo small to be seen with the naked human eye and includes prokaryotes(e.g., bacteria and mycobacteria), single cell and multiple celleukaryotes, yeast, fungi and protozoa. More specifically microorganismsupon which the compounds of this invention act are human or non-humanmammal pathogens. Pathogenic protozoa include, among others, Plasmodium,Trypanosomes and Leishmania (e.g., Leishmania major, TrypanosomaCruizii.) Fungi include Cryptococcus (e.g., Cryptococcus neoformans).Microorganism also includes parasitic nematodes.

Animals (including fish and birds) and humans are subject to infectionby nematodes which can result in debilitation long term disease.Infection by nematodes can result in significant economic loss indomestic animals and poultry. Infection may be in the gastrointestinaltract, the lymphatic system or in other tissue or organs. Nematodeparasites include, among others, Ancylostoma, Necator, Ascaris,Strongyloides, Trichinella, Capillaria, Toxocara, Toxascaris, Trichuris,Enterobius, Onchocerca, Brugia, Wuchereria, or Dracunculus. Morespecifically, nematode parasites include among others Ancylostomaduodenale, Necator americanus, Trichuris trichiura, Ascarislumbricoides, Strongyloides stercoralis, Trichinella spiralis, Toxocaracanis, Toxocara cati, Enterobius vermicularis, Onchocerca volvulus,Brugia malayi, Brugia timori, Wuchereria bancrofti, and Drancunculusmedinenis.

Diseases associated with nematode infection include filariasis(lymphatic filariasis, subcutaneous filariasis and serous cavityfilariasis), various GI tract infections (hookworm, roundworm, pinworm,whipworm, thread worm), Toxocariasis, Trichinosis, Onchocerciasis (RiverBlindness).

In a specific embodiment, compounds of this invention of any of theformulas herein can block incorporation of Galf into polysaccharidesessential for viability or virulence of pathogenic microorganisms.

In specific embodiments, the invention provides compounds of anyformulas herein which are cell permeable.

The term “alkyl” refers to a monoradical of a branched or unbranched(straight-chain or linear) saturated hydrocarbon. Alkyl groups includethose having 1 to 22 carbon atoms (C1-C22 alkyl). Alkyl groups includethose having 1-12 carbon atoms (C1-C12 alkyl). Alkyl groups includethose having 1 to 6 carbon atoms (C1-C6 alkyl) including methyl, ethyl,propyl, butyl, pentyl and hexyl groups, including all isomers thereof.In specific embodiments, alkyl groups include those having 1-3 carbons(C1-C3 alkyl groups). The term “cycloalkyl” refers to cyclic alkylgroups having 3 to 22, preferably 5-10 carbon atoms and more preferably5 or 6 carbon atoms. Cycloalkyl groups can have a single ring, may bebicyclic, tricyclic or the like. Cycloalkyl groups include, by way ofexample, single ring structures such as cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl, cyclooctyl, and the like, or multiple ringstructures such as adamantanyl, and the like. Unless otherwise indicatedalkyl groups including cycloalkyl groups are optionally substituted asdefined herein.

The term “alkylene” refers to a diradical of a branched or unbranchedsaturated hydrocarbon chain, which unless otherwise indicated can have 1to 10 carbon atoms, 1 to 6 carbon atoms, or 2-4 carbon atoms. This termis exemplified by groups such as methylene (—CH₂—), ethylene (—CH₂CH₂—),and more generally -(CH₂)n, where n is 1-10 or more preferably 1-6 or nis 1, 2, 3 or 4. Alkylene groups may be branched, e.g., by substitutionwith alkyl group substituents. Alkylene groups may be optionallysubstituted as described herein.

The term alkoxy refers to the group —OR′ where R′ is an alkyl group asdefined above.

A specific substituted alkyl group is an aryl substituted alkyl groupwhere the terms aryl and alkyl are as defined herein. In specificembodiments, the substituted alkyl group is a C1-C3 alkyl group, and inparticular is a methyl group. In specific examples the aryl group is anoptionally substituted phenyl group. In specific examples, these groupsinclude optionally substituted benzyl groups and optionally substitutedphenethyl groups.

Another specific substituted alkyl group is a halo substituted alkylgroup where alkyl is as defined above. This group includes alkyl groupshaving 1-3 carbon atoms and having 1 to 7 halogens. This groupparticularly includes alkyl groups with fluorine substitution, chlorinesubstitution and bromine substitution. A specific haloalkyl group is—CF₃.

The term “alkenyl” refers to a monoradical of a branched or unbranched(straight-chain or linear) hydrocarbon having one or more C—C doublebonds (C═C). Alkenyl groups include those having 2 to 22 carbon atoms(C2-C22 alkenyl). Alkenyl groups include those having 1-12 carbon atoms(C2-C12 alkenyl). Alkenyl groups include those having 1 to 6 carbonatoms (C2-C6 alkenyl) including ethenyl, propenyl, butenyl, pentenyl andhexyenyl groups, including all isomers thereof. In specific embodiments,alkenyl groups include those having 2 or 3 carbons (C2-C3 alkenylgroups). The term “cycloalkenyl” refers to cyclic alkenyl groups having3 to 22, preferably 5-10 carbon atoms and more preferably 5 or 6 carbonatoms and one or more C—C double bonds. Cycloalkenyl groups can have asingle ring, may be bicyclic, tricyclic or the like. Cycloalkenyl groupsinclude, by way of example, single ring structures such ascyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, cyclooctenyl,and the like, or multiple ring structures such as adamantanenyl, and thelike. Unless otherwise indicated alkenyl groups including cycloalkenylgroups are optionally substituted as defined herein. In preferredembodiments, alkenyl groups have one or two C—C double bonds which maybe conjugated. In specific embodiments, alkenyl groups and cycloalkenylgroups have a single C—C double bond.

The term “carbocyclic” is used generically herein to refer to groupswhich contain a carbon ring which may be a saturated, partiallyunsaturated or aromatic ring. Carbocyclic groups may contain one or morethan one carbon ring which ring may be a cycloakyl, unsaturatedcycloalkyl or aryl ring. Typically carbocyclic rings include thosehaving 3-12 carbon atoms in the ring. Carbocyclic rings include thosehaving two or more fused rings, bicyclic rings, tricyclic ring etc.Preferred carbocyclic rings have 6 to 12 carbon atoms. Unless otherwiseindicated carbocyclic groups are optionally substituted as definedherein.

The term “heterocyclyl” is also used generically herein to refer tocarbocyclic rings in which one or more ring carbons are replaced with aheteroatom. The heterocyclyl ring may contain a carbon ring incombination with a heteroatom containing ring. Heterocyclyl groups cancontain from one to six heteroatoms including one, two, three or fourhetero atoms. Preferred heteroatoms are N, O or S (or NR′ where R′ is ahydrogen or an optional substituent). Heterocyclyl groups can be orcontain heteroaryl groups. Unless otherwise indicated heterocyclylgroups are optionally substituted as defined herein. Heterocyclyl groupsinclude those having 5-12 ring atoms, with 1, 2 or 3 heteroatoms and 1,2 or 3 double bonds. Heterocyclyl groups include those having 5- and6-member rings with one or two nitrogens and one or two double bonds.Heterocyclyl groups include those having 5- and 6-member rings with anoxygen or a sulfur and one or two double bonds. Heterocyclyl groupsinclude those having 5- or 6-member rings and two different heteroatom,e.g., N and O, O and S or N and S. Specific heterocyclyl groups includeamong others among others, pyrrolidinyl, piperidyl, piperazinyl,pyrrolinyl, morpholinyl, oxazolyl, oxazolinyl, oxazolidinyl, indolyl,triazoly, and triazinyl groups.

The term “heterocyclyoxy” refers to the group —OR′, where R′ is anheterocyclyl group as defined above.

The term “aryl” refers to a monoradical containing at least one aromaticring. The radical is formally derived by removing a H from a ringcarbon. Aryl groups contain one or more rings at least one of which isaromatic. Rings of aryl groups may be linked by a single bond or alinker group or may be fused. Exemplary aryl groups include phenyl,biphenyl and naphthyl groups. Aryl groups include those having from 6 to30 carbon atoms. Preferred aryl groups are those containing 6-12 carbonatoms. Unless otherwise noted aryl groups are optionally substituted asdescribed herein.

The term aryoxy refers to the group —OR′, where R′ is an aryl group asdefined

The term “heteroaryl” refers to a group that contains at least onearomatic ring in which one or more of the ring carbons is replaced witha heteroatom (non-carbon atom). To satisfy valence the heteroatom may bebonded to H or a substituent groups. Ring carbons may be replaced with—O—, —S—, —NR—, —N═, —PR—, or —POR— among others, where R is an alkyl,aryl, heterocyclyl or heteroaryl group. Heteroaryl groups may includeone or more aryl groups (carbon aromatic rings) heteroaromatic and arylrings of the heteroaryl group may be linked by a single bond or a linkergroup or may be fused. Heteroaryl groups include those having aromaticrings with 5 or 6 ring atoms of which 1-3 ring atoms are heteroatoms.Preferred heteroatoms are —O—, —S—, —NR— and —N═. Heteroaryl groupsinclude those containing 5-12 ring atoms as well as those having 5 and 6ring atoms. Unless otherwise noted heteroaryl groups are optionallysubstituted as described herein. Heteroaryl groups include groups havingone or more aromatic rings in which at least one ring contains aheteroatom (a non-carbon ring atom). Heteroaryl groups include thosehaving one or two heteroaromatic rings carrying 1, 2 or 3 heteroatomsand optionally have one 6-member aromatic ring. Heteroaryl groups cancontain 5-20, 5-12 or 5-10 ring atoms. Heteroaryl groups include thosehaving one aromatic ring contains a heteroatom and one aromatic ringcontaining carbon ring atoms. Heteroaryl groups include those having oneor more 5- or 6-member aromatic heteroaromatic rings and one or more6-member carbon aromatic rings. Heteroaromatic rings can include one ormore N, O or S atoms in the ring. Heteroaromatic rings can include thosewith one, two or three N, those with one or two O, and those with one ortwo S, or combinations of one or two or three N, O or S. Specificheteroaryl groups include furyl, thienyl, pyrrolyl, imidazolyl,pyrazolyl, pyridinyl, pyrazinyl, pyrimidinyl, quinolinyl, and purinylgroups.

The term heteroaryoxy refers to the group —OR′, where R′ is a heteroarylgroup as defined

Unless otherwise specified optional substitution means substitution byone or more non-hydrogen substituents selected from halogen, hydroxyl,amine, cyano, azide, nitro, isocyanate, isothiocyanate, C1-C6 alkyl,C1-C3 alkyl, C1-C6 haloalkyl, C1-C3 haloalkyl, phenyl, benzyl, sulfate,phosphate, phosphonate, carboxyl, sulfonyl, sulfonamide, and amide. Allalkyl, aryl, heteroaryl, heterocyclyl, carbocyclic groups herein areoptionally substituted with one or more non-hydrogen substituents unlessotherwise specified. Substitution may be on one or more carbons or, iffeasible, on one or more heteroatoms, e.g., a nitrogen. The number ofsubstituents on such groups depends generally upon the nature of thegroup, but includes substitution with one, two, three, four, five or sixsubstituents.

As to any of the groups herein which contain one or more substituents,it is understood, that such groups do not contain any substitution orsubstitution patterns which are sterically impractical and/orsynthetically non-feasible. In addition, the compounds of this inventioninclude all stereochemical isomers arising from the substitution ofthese compounds.

The compounds of this invention may contain one or more chiral centers.Accordingly, this invention is intended to include racemic mixtures,diasteromers, enantiomers and mixture enriched in one or morestereoisomer. The scope of the invention as described and claimedencompasses the racemic forms of the compounds as well as the individualenantiomers and non-racemic mixtures thereof.

Treatment methods of this invention comprise the step of administeringan effective amount of one or more compounds of this invention, or asalt thereof to an individual (human and/or non-human animal) to treator prevent infection. The term “effective amount,” as used herein,refers to the amount of the compound, that, when administered to theindividual is effective to at least partially treat or preventinfection, or to at least partially ameliorate a symptom of infection.Infection herein refers to infection by a microorganism which containsthe enzyme UGM. Infection herein refers to infection by a fungus, algae,bacterium or nematode. Infection herein refers to infection by amycobacterium. As is understood in the art, the effective amount of agiven compound will depend at least in part upon, the type of infectiousorganism, the mode of administration, any carrier or vehicle (e.g.,solution, emulsion, etc.) employed, the extent of damage and thespecific individual to whom the compound is to be administered (age,weight, condition, sex, etc.). The dosage requirements needed to achievethe “effective amount” vary with the particular compositions employed,the route of administration, the severity of the symptoms presented andthe particular subject being treated. Based on the results obtained instandard pharmacological test procedures, projected daily dosages ofactive compound can be determined as is understood in the art.

Compounds of this invention can be employed in unit dosage form, e.g. astablets or capsules. In such form, the active compound or more typicallya pharmaceutical composition containing the active compound issub-divided in unit dose containing appropriate quantities of the activecompound; the unit dosage forms can be packaged compositions, forexample, packaged powders, vials, ampoules, pre-filled syringes orsachets containing liquids. The unit dosage form can be, for example, acapsule or tablet itself, or it can be the appropriate number of anysuch compositions in package form.

Any suitable form of administration can be employed in the methodherein. The compounds of this invention can, for example, beadministered in oral dosage forms including tablets, capsules, pills,powders, granules, elixirs, tinctures, suspensions, syrups andemulsions. Oral dosage forms may include sustained release or timedrelease formulations. The compounds of this invention may also beadministered topically, intravenously, intraperitoneally,subcutaneously, or intramuscularly, all using dosage forms well known tothose of ordinary skill in the pharmaceutical arts.

Pharmaceutical and veterinary compositions of the invention may also bein the form of oil-in-water or water-in-oil emulsions, where the oilyphase is any suitable oil, including vegetable or mineral oil.Emulsifying agents and/or surfactants may be included in such emulsions.In an embodiment, the compositions of the invention are formed asmicroemulsions. Methods and materials for formation of emulsions andmicroemulsions for pharmaceutical and veterinary compositions are wellknown in the art.

Pharmaceutical and veterinary compositions of the invention may be inthe form of aqueous solution or aqueous suspensions where the activeingredient is dissolved or dispersed, typically in the form of a powder,in an aqueous pharmaceutically acceptable solvent. Alternatively, activeingredients can be dispersed in an oily phase.

In another embodiment, the pharmaceutical and veterinary compositions ofthe can be in the form of pastes, gels and creams, wherein the activeingredient is dissolved in a component of the paste, gel or cream or isdispersed therein.

The therapeutically active compounds of the invention can beadministered alone, but generally will be administered with apharmaceutical carrier selected upon the basis of the chosen route ofadministration and standard pharmaceutical practice.

Pharmaceutical compositions and medicaments of this invention compriseone or more compounds in combination with a pharmaceutically acceptablecarrier, excipient, or diluent. Such compositions and medicaments areprepared in accordance with acceptable pharmaceutical procedures, suchas, for example, those described in Remington's Pharmaceutical Sciences,17th edition, ed. Alfonoso R. Gennaro, Mack Publishing Company, Easton,Pa. (1985), which is incorporated herein by reference in its entirety.

Pharmaceutically acceptable carriers are those carriers that arecompatible with the other ingredients in the formulation and arebiologically acceptable. Carriers can be solid or liquid. Solid carrierscan include one or more substances that can also act as flavoringagents, lubricants, solubilizers, suspending agents, fillers, glidants,compression aids, binders, tablet-disintegrating agents, orencapsulating materials. Liquid carriers can be used in preparingsolutions, suspensions, emulsions, syrups and elixirs. The activeingredient can be dissolved or suspended in a pharmaceuticallyacceptable liquid carrier such as water (of appropriate purity, e.g.,pyrogen-free, sterile, etc.), an organic solvent, a mixture of both, ora pharmaceutically acceptable oil or fat. The liquid carrier can containother suitable pharmaceutical additives such as, for example,solubilizers, emulsifiers, buffers, preservatives, sweeteners, flavoringagents, suspending agents, thickening agents, colors, viscosityregulators, stabilizers or osmo-regulators. Compositions for oraladministration can be in either liquid or solid form.

The compounds of the present inventions may form salts which are alsowithin the scope of this invention. Reference to a compound of theformulas herein is understood to include reference to salts thereof,unless otherwise indicated. The term “salt(s)”, as employed herein,denotes acidic and/or basic salts formed with inorganic and/or organicacids and bases. In addition, when a compound of a formula hereincontains both a basic moiety, such as, but not limited to an amine or apyridine ring, and an acidic moiety, such as, but not limited to, acarboxylic acid, zwitterions (“inner salts”) may be formed and areincluded within the term “salt(s)” as used herein. Pharmaceuticallyacceptable (i.e., non-toxic, physiologically acceptable) salts arepreferred, although other salts are also useful, e.g., in isolation orpurification steps which may be employed during preparation. Salts ofthe compounds of the formula I may be formed, for example, by reacting acompound of the formula I with an amount of acid or base, such as anequivalent amount, in a medium such as one in which the saltprecipitates or in an aqueous medium followed by lyophilization.

Exemplary acid addition salts include acetates (such as those formedwith acetic acid or trihaloacetic acid, for example, trifluoroaceticacid), adipates, alginates, ascorbates, aspartates, benzoates,benzenesulfonates, bisulfates, borates, butyrates, citrates,camphorates, camphorsulfonates, cyclopentanepropionates, digluconates,dodecylsulfates, ethanesulfonates, fumarates, glucoheptanoates,glycerophosphates, hemisulfates, heptanoates, hexanoates, hydrochlorides(formed with hydrochloric acid), hydrobromides (formed with hydrogenbromide), hydroiodides, 2-hydroxyethanesulfonates, lactates, maleates(formed with maleic acid), methanesulfonates (formed withmethanesulfonic acid), 2-naphthalenesulfonates, nicotinates, nitrates,oxalates, pectinates, persulfates, 3-phenylpropionates, phosphates,picrates, pivalates, propionates, salicylates, succinates, sulfates(such as those formed with sulfuric acid), sulfonates (such as thosementioned herein), tartrates, thiocyanates, toluenesulfonates such astosylates, undecanoates, and the like.

Exemplary basic salts include ammonium salts, alkali metal salts such assodium, lithium, and potassium salts, alkaline earth metal salts such ascalcium and magnesium salts, salts with organic bases (for example,organic amines) such as benzathines, dicyclohexylamines, hydrabamines[formed with N,N-bis(dehydro-abietyl)ethylenediamine],N-methyl-D-glucamines, N-methyl-D-glucamides, t-butyl amines, and saltswith amino acids such as arginine, lysine and the like. Basicnitrogen-containing groups may be quaternized with agents such as loweralkyl halides (e.g., methyl, ethyl, propyl, and butyl chlorides,bromides and iodides), dialkyl sulfates (e.g., dimethyl, diethyl,dibutyl, and diamyl sulfates), long chain halides (e.g., decyl, lauryl,myristyl and stearyl chlorides, bromides and iodides), aralkyl halides(e.g., benzyl and phenethyl bromides), and others.

Compounds of the present invention, and salts thereof, may exist intheir tautomeric form, in which hydrogen atoms are transposed to otherparts of the molecules and the chemical bonds between the atoms of themolecules are consequently rearranged. It should be understood that alltautomeric forms, insofar as they may exist, are included within theinvention. Additionally, inventive compounds may have trans and cisisomers and may contain one or more chiral centers, therefore exist inenantiomeric and diastereomeric forms. The invention includes all suchisomers, as well as mixtures of cis and trans isomers, mixtures ofdiastereomers and racemic mixtures of enantiomers (optical isomers).When no specific mention is made of the configuration (cis, trans or Ror S) of a compound (or of an asymmetric carbon), then any one of theisomers or a mixture of more than one isomer is intended. The processesfor preparation can use racemates, enantiomers, or diastereomers asstarting materials. When enantiomeric or diastereomeric products areprepared, they can be separated by conventional methods, for example, bychromatographic or fractional crystallization. The inventive compoundsmay be in the free or hydrate form.

Well-known methods for assessment of drugability can be used to furtherassess active compounds of the invention for application to giventherapeutic application. The term “drugability” relates topharmaceutical properties of a prospective drug for administration,distribution, metabolism and excretion. Drugability is assessed invarious ways in the art. For example, the “Lipinski Rule of 5” fordetermining drug-like characteristics in a molecule related to in vivoabsorption and permeability can be applied (C. A. Lipinski, F. Lombardo,B. W. Dominy, P. J. Feeney, Experimental and computational approaches toestimate solubility and permeability in drug discovery and developmentsettings, Adv. Drug Del. Rev., 2001, 46, 3-26 and Arup K. Ghose,Vellarkad N. Viswanadhan, and John J. Wendoloski, A Knowledge-BasedApproach in Designing Combinatorial or Medicinal Chemistry Libraries forDrug Discovery, J. Combin. Chem., 1999, 1, 55-68.)

In general a preferred drug for oral administration exhibits no morethan one violation of the following rules:

(1) Not more than 5 hydrogen bond donors (e.g., nitrogen or oxygen atomswith one or more hydrogens);

(2) Not more than 10 hydrogen bond acceptors (e.g., nitrogen or oxygenatoms);

(3) Molecular weight under 500 g/mol and more preferably between 160 and480; or

(4) log P less than 5 and more preferably between −0.4 to +5.6 and yetmore preferably −1<log P<2. Methods for calculating or experimentallydetermining log P are well-known in the art. Compounds of this inventionpreferred for therapeutic application include those that do not violateone or more of 1-4 above.

Compounds of this invention preferred for therapeutic applicationinclude those having log P less than 5 and more preferably between −0.4to +5.6 and yet more preferably −1<log P<2.

When a group of substituents is disclosed herein, it is understood thatall individual members of that group and all subgroups, including anyisomers, enantiomers, and diastereomers of the group members, aredisclosed separately. When a Markush group or other grouping is usedherein, all individual members of the group and all combinations andsubcombinations possible of the group are intended to be individuallyincluded in the disclosure. A number of specific groups of variabledefinitions have been described herein. It is intended that allcombinations and subcombinations of the specific groups of variabledefinitions are individually included in this disclosure.

Compounds described herein may exist in one or more isomeric forms,e.g., structural or optical isomers. When a compound is described hereinsuch that a particular isomer, enantiomer or diastereomer of thecompound is not specified, for example, in a formula or in a chemicalname, that description is intended to include each isomers andenantiomer (e.g., cis/trans isomers, R/S enantiomers) of the compounddescribed individual or in any combination. Additionally, unlessotherwise specified, all isotopic variants of compounds disclosed hereinare intended to be encompassed by the disclosure. For example, it willbe understood that any one or more hydrogens in a molecule disclosed canbe replaced with deuterium or tritium. Isotopic variants of a moleculeare generally useful as standards in assays for the molecule and inchemical and biological research related to the molecule or its use.Isotopic variants, including those carrying radioisotopes, may also beuseful in diagnostic assays and in therapeutics. Methods for making suchisotopic variants are known in the art.

Specific names of compounds are intended to be exemplary, as it is knownthat one of ordinary skill in the art can name the same compoundsdifferently.

Molecules disclosed herein may contain one or more ionizable groups[groups from which a proton can be removed (e.g., —COOH) or added (e.g.,amines) or which can be quaternized (e.g., amines)]. All possible ionicforms of such molecules and salts thereof are intended to be includedindividually in the disclosure herein. With regard to salts of thecompounds herein, one of ordinary skill in the art can select from amonga wide variety of available counterions those that are appropriate forpreparation of salts of this invention for a given application. Inspecific applications, the selection of a given anion or cation forpreparation of a salt may result in increased or decreased solubility ofthat salt.

Every formulation or combination of components described or exemplifiedherein can be used to practice the invention, unless otherwise stated.The invention illustratively described herein suitably may be practicedin the absence of any element or elements, limitation or limitationswhich is not specifically disclosed herein.

It is understood that this invention is not limited to the particularmethodology, protocols, cell lines, and reagents described, as these mayvary. It is also to be understood that the terminology used herein isfor the purpose of describing particular embodiments only, and is notintended to limit the scope of the present invention which will belimited only by the appended claims.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include plural reference unless thecontext clearly dictates otherwise. Thus, for example, reference to “acell” includes a plurality of such cells and equivalents thereof knownto those skilled in the art, and so forth. As well, the terms “a” (or“an”), “one or more” and “at least one” can be used interchangeablyherein.

Whenever a range is given in the specification, for example, atemperature range, a time range, or a composition or concentrationrange, all intermediate ranges and subranges, as well as all individualvalues included in the ranges given are intended to be included in thedisclosure. It will be understood that any subranges or individualvalues in a range or subrange that are included in the descriptionherein can be excluded from the claims herein.

All patents and publications mentioned in the specification areindicative of the levels of skill of those skilled in the art to whichthe invention pertains. References cited herein are incorporated byreference herein in their entirety to indicate the state of the art asof their publication or filing date and it is intended that thisinformation can be employed herein, if needed, to exclude specificembodiments that are in the prior art. For example, when composition ofmatter are claimed, it should be understood that compounds known andavailable in the art prior to Applicant's invention, including compoundsfor which an enabling disclosure is provided in the references citedherein, are not intended to be included in the composition of matterclaims herein.

THE EXAMPLES

Screening

The Protein Data Bank contains several UGM crystal structures; however,only two present a bacterial UGM poised for catalysis and complexed withthe UDP-Galp substrate. Of these, the structure of substrate-bound K.pneumoniae UGM (KpUGM) (PDB ID: 3INT) [Gruber, T. D., et al., X-raycrystallography reveals a reduced substrate complex ofUDP-galactopyranose mutase poised for covalent catalysis by flavin.Biochemistry, 2009. 48(39): p. 9171-3] was chosen as the starting pointfor virtual screening with DOCK. In this structure, the enzyme is in theactive form, with the flavin adenine dinucleotide (FAD) cofactor reducedand a flexible loop (residues 166-178) closed over the active site.

In order to evaluate different sampling parameters for the docking, aset of 1,700 property matched decoys [Mysinger, M. M., et al., Directoryof useful decoys, enhanced (DUD-E): better ligands and decoys for betterbenchmarking. J Med Chem, 2012. 55(14): p. 6582-94] for a set of knownbinders from the 2-aminothiazole (AT) (n=25) [Dykhuizen et al. 2008] andthiazolidinones TZ (n=13) [Dykhuizen et al. 2008; Carlson et al. 2006]scaffolds (FIG. 7) was created. The decoys and known binders were dockedand the adjusted log AUC [Mysinger et al. 2010; Irwin, J. J., et al.,ZINC: a free tool to discover chemistry for biology. J Chem Inf Model,2012. 52(7): p. 1757-68] was assessed. LogAUC is a measure of theability of docking to enrich for the known binders over decoys, whichemphasizes early enrichment. A random ranking will yield a value of logAUC=0.

The optimal docking configuration led to a log AUC=34.5 for all 38 knownbinders and log AUC=54.8 when considering just ligands from the ATseries (FIG. 2A). AT ligands exhibited much better docking scores thanTZ ligands. TZ are well-documented pan-assay Interference compounds[Baell, J. B. and G. A. Holloway, New substructure filters for removalof pan assay interference compounds (PAINS) from screening libraries andfor their exclusion in bioassays. J Med Chem, 2010. 53(7): p. 2719-40]and it has been proposed in the past that the TZ ligands actually bindto UGM via a covalent binding mechanism [Carlson et al. 2006]. Thisexplains their poor performance in the docking.

Using the same docking configuration, a library of 4.7 million lead-likemolecules (250<molecular weight<350; xLogP<3.5; number of rotatablebonds≦7 [Teague, S. J., et al., The Design of Leadlike CombinatorialLibraries. Angew Chem Int Ed Engl, 1999. 38(24): p. 3743-3748; Irwin etal. 2012]) were processed with DOCK against UGM. AT ligands showed verygood enrichment against this much larger set as well, With log AUC=46.3(FIG. 2B). This encouraged selection of potential inhibitors forexperimental testing.

Thirteen of the 0.01% top-ranking molecules from the docking screen(FIG. 3A, provides structures) were manually selected for in vitroanalysis. Criteria for selection included a negative charge forinteraction with two catalytically crucial arginine residues in the UGMactive site [Chad, J. M., et al., Site-directed mutagenesis ofUDP-galactopyranose mutase reveals a critical role for the active-site,conserved arginine residues. Biochemistry, 2007. 46(23): p. 6723-32].Additional orthogonal criteria that are omitted in the docking scoringfunction were also considered, such as probable protonation states,internal ligand strain, and chemical diversity.

A high pressure liquid chromatography (HPLC) based assay [Lee, R., etal., Enzymatic Synthesis of UDP-Galactofuranose and an Assay forUDP-Galactopyranose Mutase Based on High-Performance LiquidChromatography. Anal Biochem, 1996: p. 1-7] was used to monitorinhibition of UGM activity by the 13 selected molecules (FIG. 3B). At100 μM, six molecules showed more than 25% inhibition of KpUGM activity.Five of these molecules showed dose-dependent inhibition, ranging 15-33%inhibition at 50 μM. To eliminate aggregation-based non-specificinhibition [McGovern, S. L., et al., A common mechanism underlyingpromiscuous inhibitors from virtual and high-throughput screening. J MedChem, 2002. 45(8): p. 1712-22] we repeated the assay in the presence ofdetergent (0.025% Tween 80). Three of the 13 compounds were sensitive todetergent, showing reversal of inhibition (FIG. 8) and were not furtherconsidered.

Compounds 6 and 10 were selected as the two most promising inhibitors.Dynamic light scattering (DLS) indicated that these compounds do notform detectible colloids at 100 μM (FIGS. 9A-9G 3). Additionally, theydo not display any inhibition of AmpC β-lactamase, an unrelatedhydrolase, at 100 μM. This gave confidence that the observed UGMinhibition was not an artifact of small molecule aggregation. Compounds6 and 10 were then tested in the previously reported FP assay,inhibiting KpUGM with Kd(6)=62 μM and Kd(10)=9 μM, FIG. 10A and FIG. 10Brespectively.

To study SAR of 6 and 10, commercially available analogs of the leadswere purchased and tested. One analog of 10 (FIG. 11A shows structuresof compounds 10, 14 and 18), i.e., compound 14, showed improved KpUGMinhibition (FIG. 11B), and slightly tighter binding than compound 10(FIG. 11C). A lack of additional purchasable analogs as well assolubility issues further pursuing this series. Compound 6, on the otherhand, had many commercially available analogs. Compound 6 displayedcompetitive inhibition of KpUGM in Lineweaver-Burk analysis with a K_(i)of 78 μM (FIG. 12), similar to the K_(d) value for 6 obtained in the FPassay. Eleven analogs of 6 were selected and sourced for testing. Eightanalogs showed improved inhibition of KpUGM (FIG. 6) with up to 96%/88%inhibition at 100 μM/50 μM in the HPLC assay. The best performingmolecules (19, 22, and 24) were also tested in the FP assay, displayingK_(d) values of 15 μM, 9 μM, and 9 μM respectively (FIG. 4A and FIGS.13A and 13B).

While DLS indicated that 19 and 24 form colloidal aggregates at aconcentration of 100 μM, 22 did not show any aggregation at thisconcentration (FIGS. 9A-G). Lineweaver-Burk analysis indicated 22 is acompetitive inhibitor with K_(i) of 7 μM (FIG. 4C), which is inaccordance with the FP assay results for the compound.

The specificity of in vitro UGM inhibition was assessed using purifiedrecombinant UGM homologs. MtUGM and C. diptheriae UGM (CdUGM) shareabout 43% sequence identity with KpUGM, and 76% identity with eachother. However, active site residues are highly conserved between thehomologs. Interestingly, 22 showed much lower inhibition towards MtUGM(19% at 100 μM) than KpUGM. Yet, inhibition of CdUGM (38% at 100 μM) by22 proved slightly better than for MtUGM. This trend was consistent forother analogs from this series (FIG. 14). The fact that these compoundsare more potent inhibitors of KpUGM may be a consequence of performingthe docking screen with a KpUGM structure.

To gain insight for scaffold optimization, the binding mode ofinhibitors from this series by co-crystallization of UGM and 22 wasstudied. Attempts at co-crystallizing KpUGM with 22 resulted in crystalsthat diffracted, but twinning prevented the structure from being solved.However, it was possible to solve the crystal structure of CdUGM incomplex with 22 to 2.7 Å resolution (not shown) (Table 1). Thisstructure is the first co-crystal structure of UGM in complex with asmall molecule inhibitor.

CdUGM crystalized in an open conformation, in contrast to the closedconformation KpUGM structure used for the virtual screen. Compound 22indeed binds in the active site (not shown). The carboxylate of theinhibitor forms a salt bridge with Arg289, a residue essential for UGMactivity [Sanders, D. A. R., et al., UDP-galactopyranose mutase has anovel structure and mechanism. Nat Struct Mol Biol, 2001: p. 1-6]. TheR₁ thiophene of 22 binds in a hydrophobic pocket formed by Tyr327,Tyr365, Trp163 and Pro328. The R₂ chlorophenyl moiety of the inhibitorstacks on top of Tyr327 and π-stacks against Trp163. The co-crystalstructure suggests the chlorine atom of 22 may form a halogen bond withthe side chain hydroxyl of Ser216.

Overlay of the new crystal structure with the KpUGM structure used fordocking results in a clash of 22 with Arg174. This essential residue islocated on the flexible loop and thus moves into the UGM active site inthe active, reduced form of the enzyme. It is possible that thisarginine could adopt a different rotamer to accommodate 22 upon lidclosure. The predicted docking pose of 6 places it in the same bindingpocket and predicts salt bridge formation with Arg289. However, theoverall binding modes of the ligands are quite different due to theopposing conformations of the flexible loop (not shown).

The structure of the complex can also explain some of the SAR witnessedin this series (FIG. 6). Specifically, larger para substitutions on theR₂ phenyl ring perform better: pCl-Phe (21)>pMe-Phe (25)>pF-Phe (16)>Phe(6). pCl-Phe performs especially well, compare 21 with 6, possibly dueto the potential halogen bond. Thiophene R₂ also improved inhibition(20). From the R₁ side, bigger moieties performed better: e.g.19>18>6>17; 24>25 ; 22>26>21. The placement of R₁ in the structureindeed allows for much larger moieties.

It should be noted that this SAR is based on UGM inhibition of the smallmolecules at 100 μM, a concentration at which some compounds from thisseries might be prone to colloid formation (FIGS. 9A-G). Nonetheless,five additional commercially available “second generation” analogs wereselected and tested based on this SAR that combine favorable R₁ and R₂side chains (FIG. 6). All second generation analogs showed more than 90%inhibition of KpUGM at 100 μM, with three of the five showing more than90% inhibition at 50 μM. The best inhibitor (30) showed no measurableactivity of KpUGM at either of these two concentrations (FIG. 6).Compound 30 was further characterized by Lineweaver-Burk analysis aswell as in the FP assay (FIGS. 4B and 4D). Both assays indicated that 30is a competitive inhibitor of UGM, displaying a K_(i) and K_(d) of 1.1μM and 4.5 μM, respectively.

Similar to 19 and 24, compound 30 forms colloidal aggregates at 100 μM(FIG. 9F). Indeed, 30 showed non-specific inhibition of the unrelatedenzymes AmpC and malate dehydrogenase (MDH) at high concentrations.However, the critical aggregation concentration of 30, as determined bya full dose response curve for MDH inhibition (IC₅₀ =55.7 μM; FIG. 15),is significantly higher than its K_(i) for KpUGM. While MDH inhibitionwas fully rescued by the addition of detergent, competitive binding of30 to UGM in the FP assay proved insensitive to detergent (FIG. 16).Taken together with the Lineweaver-Burk analysis, we conclude that UGMinhibition by 30 is competitive specific and not mediated by colloids.

Encouraged by the in vitro properties of molecules from this series,antibacterial activity was assessed via two cell-based approaches: diskdiffusion and broth microdilution assays. Growth curves of Mycobacteriumsmegmatis, a fast-growing and nonpathogenic model for M. tuberculosis,were generated in liquid media with varied concentrations of our mostpromising UGM inhibitors. Trends in growth inhibition of M. smegmatisaligned well with the measured in vitro properties of our series (FIGS.4A-4E, FIG. 5). The minimal inhibitory concentration (MIC) of 30 for M.smegmatis was determined to be 20 μM. Compound 30 showed no significantcell-killing with control bacterial strains that do not possess a UGMortholog, such as B. subtilis. (MIC=500 μM) and B strain E. coli(MIC>500 μM).

Similar results were obtained in a disk diffusion assay conducted onsolid media (FIG. 5). In this experiment, a zone of growth inhibitionaround a treated disk was measured. Again, compound 30 outperformed allother compounds of the series. Though B. subtilis growth inhibition wasseen with 30, the zone of inhibition was significantly smaller than thatobserved for M. smegmatis. No cell-killing of E. coli occurred at thetested concentration.

Additionally, the cytotoxicity of example inhibitor compound 30 withHEK293 cells (FIG. 17) was assessed. Compound 30 was found to be onlymildly toxic (LD_(50˜100) μM) relative to its MIC for M. smegmatis(5-fold difference), leaving a wide therapeutic window.

This work demonstrates that virtual screening is an effective method foridentifying small molecule ligands of proteins that have provenchallenging in biochemical, target-based HTS. The work provides thefirst crystal structure of a UGM-inhibitor complex, which may informfuture inhibitor design and shed light on specificity determinants ofUGM inhibition. The work identified and characterized compounds (FormulaI and II) with potent antimycobacterial activity and attractive featuresfor future optimization.

Docking can be a complementary tool to HTS. Regardless of whether thesame [Ferreira et al. 2010; Brenk, R., J. J. Irwin, and B. K. Shoichet,Here be dragons: docking and screening in an uncharted region ofchemical space. J Biomol Screen, 2005. 10(7): p. 667-74] or different[Doman, T. N., et al., Molecular docking and high-throughput screeningfor novel inhibitors of protein tyrosine phosphatase-1B. J Med Chem,2002. 45(11): p. 2213-21] libraries are being screened, docking tends tohave higher hit rates and produce chemically novel hits. This studyreinforces these observed trends. Several HTS campaigns were performedagainst Kp and MtUGM, screening close to 400,000 molecules in total(PubChem [Wang, Y., et al., PubChem: a public information system foranalyzing bioactivities of small molecules. Nucleic Acids Res, 2009. 37(Web Server issue): p. W623-33] AID: 504406). These endeavors resultedin only a few hits, some of which are uridine analogs [Soltero-Higgin etal. 2004, Scherman, M. S., et al., Drug targeting Mycobacteriumtuberculosis cell wall synthesis: development of a microtiterplate-based screen for UDP-galactopyranose mutase and identification ofan inhibitor from a uridine-based library. Antimicrob Agents Chemother,2003. 47(1): p. 378-82] and others, namely the TZ series of molecules,are known frequent hitters in HTS [Baell et al. 2010]. Interestingly,compounds 3 and 24 were included in a compound library screened againstMtUGM, but they were not detected by HTS. This highlights a majordownfall of HTS: false negatives and assay dependence. In the FP assayused for these HTS, displacement of a substrate analog probe gives aread out, limiting the assay to identifying only competitive inhibitorsof UGM. Further characterization of 3 may reveal the compound acts onUGM via a different mode of inhibition, explaining why it did not appearas a hit in previous HTS. Compound 24, on the other hand, may have beenoverlooked by the stringency of HTS. The HTS containing 24 was runagainst MtUGM. Our results with this series suggest that KpUGM is easierto inhibit than MtUGM (inhibitors are about an order of magnitude morepotent against KpUGM in vitro). Thus, 24 may have shown up in previousHTS had KpUGM been the target, or had the defined hit parameters beenrelaxed. Virtual screening bypassed these HTS shortcomings by allowingmore thorough characterization of a much smaller set of candidates.

Virtual screening and docking, of course, have their own caveats. ThoughUGM possesses a flexible loop as a vital part of its active site,docking only utilizes a single static conformation of the target forscreening. HTS, in a sense, targets all protein conformations at once.The determined CdUGM co-crystal structure displays the flexible loop ina radically different conformation than the docking target, underscoringthe need for specific consideration of this loop during virtualscreening. Utilizing our CdUGM structure to seed future UGM dockingscreens may enable discovery of different classes of UGM inhibitors.

The newly determined CdUGM structure is a major advancement on severalfronts. It is the first crystal structure of UGM from C. diphtheria,adding to the small number of available bacterial UGM structures frompathogenic species. Moreover, it is the first structure of UGM incomplex with a small molecule inhibitor. The structure helps explain SARin our inhibitor series and will be instrumental in propelling futureoptimization. As discussed previously, the observed conformation ofCdUGM underscores the importance of the flexible loop (CdUGM residues169-181). While the UGM active site is highly conserved across bacterialspecies, some variability exists in the flexible loop region. Differentconformations of the loop may be stabilized by sequence elements distalto the binding site of our compounds. This could account for thepreferential binding of our inhibitors to distinct UGM orthologs. Thedynamics and conformational preferences of this loop warrant furtherinvestigation.

While the experimentally determined binding mode of 22 differs from thedocking prediction, it remains to be seen which binding mode holds truefor KpUGM. Indeed, re-docking of 22 to the CdUGM co-crystal structureclosely recapitulates its binding mode. However, this should not hinderthe fact that we now have in hand a novel and promising starting pointfor optimization of a specific antimycobacterial chemotype. Compound 30is chemically different than any known MtUGM inhibitor in ChEMBL,[Gaulton, A., et al., ChEMBL: a large-scale bioactivity database fordrug discovery. Nucleic Acids Res, 2012. 40 (Database issue): p.D1100-7] with a chemical similarity score (Tanimoto-coefficient usingECFP4)≦0.16 as well as from any known ligand used in our training set(Tc≦0.24).

Furthermore, the series identified offer straightforward syntheticchemical routes for medicinal chemistry optimization. Derivatives of ourscaffold are accessible via combinations of commercially availablebuilding blocks having different R₁ and R₂ or different R₆ and R₇. Inaddition to facile synthesis, several features make this seriesparticularly appealing. These include stable SAR, and correspondencebetween in vitro inhibition and antimycobacterial activity, suggestingefficient cell permeability. Taken together, these features representmarked improvements over earlier UGM inhibitors [Dykhuizen et al 2008],some of which may suffer from off-target effects and toxicity issues[Borrelli et al. 2010].

An interesting characteristic of this series is its aggregationproperties. DLS shows that several molecules from the series (e.g. theoriginal docking hit 6 and 22) do not aggregate at concentrations up to100 μM. Other analogs such as 19, 24 and 30 show aggregation at highconcentrations (FIGS. 9A-9G); however, non-specific enzyme inhibitionassays and detergent controls (FIGS. 8, 9A-9G, 15 and 16) verified thatthe UGM inhibition observed for the molecules prone to colloidalformation was achieved at concentrations below their criticalaggregation concentration. This property should be kept in mind infuture optimization of this chemotype. In fact, in some scenarios smallmolecule aggregation might provide beneficial pharmacokinetics [Owen, S.C., et al., Colloidal aggregation affects the efficacy of anticancerdrugs in cell culture. ACS Chem Biol, 2012. 7(8): p. 1429-35].

Molecular docking was performed with DOCK 3.6 with scoring includingrapid context-dependent ligand desolvation using the solvent-excludedvolume method as described in [Mysinger et al. 2010], DelPhi [Gilson, M.K. and B. Honig, Calculation of the total electrostatic energy of amacromolecular system: solvation energies, binding energies, andconformational analysis. Proteins, 1988. 4(1): p. 7-18] basedelectrostatics and a thin layer of electrostatic spheres as described in[Mysinger, M. M., et al., Structure-based ligand discovery for theprotein-protein interface of chemokine receptor CXCR4. Proc Natl AcadSci USA, 2012. 109(14):5517-22]. Sampling parameters were varied andassess by enrichment of known ligands over decoys as described in theresults including the following: (final parameters are bolded).distance_tolerance=1.5, 2.0, 2.3, 2.5, 3.0 (Å);ligand_binsize/receptor_binsize 0.2, 0.3, 0.4, 0.5, 1.0 (Å) ;ligand_overlap/receptor_overlap 0.1, 0.4, 0.5, 0.6, 0.7, 1.0, 1.5 (Å).45 matching spheres were used based on the crystallographic ligand.Final energies were computed after 250 steps of rigid-body minimization.

A single rotamer change was introduced to PDB 3INT chain B based on aminimization of the predicted DOCK pose of a known ligand (#14 inSupplementary FIG. 1) using RosettaLigand [Davis, I. W. and D. Baker,RosettaLigand docking with full ligand and receptor flexibility. J MolBiol, 2009. 385(2): p. 381-92] Rosetta command line:ligand_dock.static.linuxgccrelease-scomplex.pdb-database<database>-extra_res_fa lig.params-nstruct10-ligand:minimize_ligand-ligand:harmonic_torsions10-ligand:soft_rep-ligand:old_estat-packing::ex1-packing::ex1aro-packing::ex2-packing::extrachi_cutoff1

The docking property matched decoys were generated by the DUD-E Server[Mysinger, M. M., et al, 2012].

Fifty decoys were generated for each of the 38 ligands described in FIG.7. For the final virtual screen, ZINC's [Irwin et al. 2012]pre-generated lead-like subset (subset 1) was docked containing 4.7million molecules at the time.

Selection of Candidates For Testing

The top 500 molecules from the virtual screen were filtered via Marvin(ChemAxon, Budapest, Hungary) to assess correct protonation state of themolecules. SMARTS filter calculation was performed through theSmartsfilter web application, Division of Biocomputing, Dept. of Biochem& Mol Biology, University of New Mexico, Albuquerque, N.M., (web sitepangolin.health.unm.edu/tomcat/biocomp/smartsfilter) to remove potentialreactive molecules or frequent non-specific hitters [Baell et al. 2010].The rest of the molecules were scrutinized manually by visual inspectionto assess characteristics orthogonal to the scoring function such asoverly strained conformations, and simple availability from vendors.Compound similarity was calculated using ECFP4-based Tanimotocoefficients [Rogers, D. and M. Hahn, Extended-connectivityfingerprints. J Chem Inf Model, 2010. 50(5): p. 742-54.] as implementedin Pipeline-Pilot [Pilot, P., version 6.1; SciTegic Inc.: San Diego,Calif. 92123-1365].

Dynamic light scattering. To evaluate aggregation by DLS compounds werediluted from concentrated stocks in DMSO into filtered 50 mM potassiumphosphate, pH 7.0. The final DMSO concentration was 1%, and compoundconcentrations were usually 100 μM. Samples were run in duplicates. Allmeasurements were made at room temperature using a DynaPro MS/X (WyattTechnology) with a 55 mW laser at 826.6 nm. The laser power was 100%,and the detector angle was 90°.

Aggregation counter screens. Compounds were tested for inhibition ofMalate Dehydrogenase and AmpC β-lactamase as reported. Assays wereperformed in 50 mM potassium phosphate buffer, pH 7.0 at 25° C. For AmpCthe molecules were mixed with buffer and CENTA substrate (50 μM; TydockPharma; Modena, Italy) to a final concentration of 1% DMSO (v/v).Reactions were initiated by addition of β-Lactamase (1 nM). Change inabsorbance was monitored at 405 nm for 3 minutes. For MalateDehydrogenase assay (MDH; Sigma Cat# M-7032), the molecule was mixedwith buffer and 2 nM final concentration of the enzyme to a finalconcentration of 1% DMSO (v/v) and were incubated for five minutes. MDHreactions were started by adding substrates: Oxaloacetic acid (20 mMstock in buffer, prepared fresh daily; Sigma Cat# 04126) to a finalconcentration 200 μM and NADH (20 mM stock in buffer—prepare freshdaily; Sigma Cat# N-4505) to a final concentration 200 μM. Change inabsorbance was monitored at 410 nm for 2.5 minutes. Absorbance wasmonitored on an HP 8453 UV-visible spectrophotometer (Agilent,Technologies, Santa Clara, Calif.). The assays were performed induplicate in methacrylate disposable cuvettes.

Compound sources. Compounds were sourced from the following vendors:compounds 1, 5, 12, 13 from Chembridge, compounds 3,4 from Pharmeks,compounds 8,11 from Vitas-M laboratory, 2,6,7,9,10 and 14-31 fromEnamine. All compounds were sourced at 95% or greater purity asdescribed by the vendors.

Recombinant protein expression and purification. KpUGM and MtbUGM wererecombinantly expressed and purified as previously described with slightmodifications [Carlson et al. 2006; Gruber, T. D., et al., LigandBinding and Substrate Discrimination by UDP-Galactopyranose Mutase. JMol Biol, 2009. 391(2): p. 327-340]. Briefly, E. coli BL21 (DE3) cellscontaining KpUGM-pGEMEasy or MtUGM-pET-29b constructs were grown in LBwith 100 μg/ml ampicillin or 50 μg/ml kanamycin. When cells reachedmid-log phase, recombinant protein expression was induced with 0.1 mMIPTG and cells were grown overnight at 15° C. Cells were harvested andlysed as before, and the His-tagged proteins were purified viaNi-affinity chromatography on an ÄKTA FPLC (Amersham Biosciences)[Carlson et al. 2006; Gruber et al. 2009]. Protein aliquots werevitrified in liquid nitrogen and stored at −80° C.

Open reading frame coding for residue 18-404 of CdUGM was amplified fromgenomic DNA of C. diphtheriae NCTC 13129 (ATCC). The PCR product wascloned into a modified pMALc5x vector, resulting in a N-terminallyHis-tagged UGM with a TEV cleavage site. The expression plasmid wastransformed into Escherichia coli ER2523 and expression was induced with0.1 mM IPTG at 15° C. when the optical density reached 0.6. Protein waspurified as previously described for KpUGM [Beis, K., et al., CrystalStructures of Mycobacteria tuberculosis and Klebsiella pneumoniaeUDP-Galactopyranose Mutase in the Oxidised State and Klebsiellapneumoniae UDP-Galactopyranose Mutase in the (Active) Reduced State. JMol Biol, 2005. 348(4): p. 971-982].

Crystallography. Purified CdUGM was extensively dialyzed against 20 mMTris-HCl (pH 7) and concentrated to 10 mg/mL. The concentration ofprotein was based on FAD content measured as absorbance at 450 nm usingan extinction coefficient of 11300 M⁻¹cm⁻¹. Compound 22 (50 mM stock inDMSO) was added to achieve final concentration of 5 mM 22 and 9 mg/mLCdUGM. Hanging drop vapor diffusion was performed by mixing 2 μL ofprotein solution and 2 μL of well solution (100 mM Bis-Tris (pH 6.5), 2M ammonium sulfate), and equilibrating against 500 μL of the wellsolution. Crystals appeared and grew to full size within 2 weeks. Thecrystals were cryoprotected by briefly swipping through 100 mM Bis-Tris(pH 6.5), 2.5 M ammonium sulfate, and 15% glycerol, and then vitrifiedand stored in liquid nitrogen. Single crystal diffraction data wascollected at beamline X25 at National Synchrotron Light Source,Brookhaven National Laboratory. Data reduction and scaling wereperformed with HKL2000 (Table 1) [Otwinowski, Z. and W. Minor,Processing of x-ray diffraction data collected in oscillation mode, inMethods in enzymology: macromolecular crystallography, part A, J. C. W.Carter and R. M. Sweet, Editors. 1997, Academic Press New York. p.307-326]. Molecular replacement was performed with PHENIX AutoMR [Adams,P. D., et al., PHENIX: a comprehensive Python-based system formacromolecular structure solution. Acta Crystallogr D Biol Crystallogr,2010. 66: p. 213-22139; McCoy, A. J., et al., Phaser crystallographicsoftware. J Appl Crystallogr, 2007. 40: p. 658-674] using a previouslyreported Escherichia coli UGM structure (PDB ID: 1I8T) [Sander et al.2001] as a search model. FAD and 22 coordinates and restraints weregenerated using eLBOW [Moriarty, N., R. Grosse-Kunstleve, and P. Adams,Electronic Ligand Builder and Optimization Workbench (eLBOW): a tool forligand coordinate and restraint generation. Acta Crystallogr D BiolCrystallogr, 2009. 65: p. 1074-1080]. Model adjustment and refinementwere performed in Coot [Emsley, P., et al., Features and development ofCoot. Acta Crystallogr D Biol Crystallogr, 2010. 66: p. 486-501] andphenix.refine [Afonine, P. V., R. W. Grosse-Kunstleve, and P. D. Adams,The Phenix refinement framework. CCP4 Newsl, 2005. 42: p. 8],respectively (Table 1). The model was validated using MolProbity [Chen,V. B., et al., MolProbity: all-atom structure validation formacromolecular crystallography. Acta Crystallogr D Biol Crystallogr,2010. 66: p. 12-21]. Crystal structure figures were generated with PyMOL[DeLano, W. L., The PyMOL molecular graphics system. 2002].

UGM in vitro inhibition. Enzymatic activity of recombinant UGM wasmonitored using an HPLC-based assay [Wesener et al., 2013; Lee et al.1996; Zhang, Q. and H.-w. Liu, Studies of UDP-Galactopyranose Mutasefrom Escherichia coli: An Unusual Role of Reduced FAD in Its Catalysis.J. Amer. Chem. Soc., 2000. 122(38): p. 9065-9070]. Reactions wereperformed in duplicate at 22° C. in 50 mM NaH2PO4 buffer (pH 7) with 20nM enzyme and 20 mM fresh sodium dithionite. Small molecules were addedfrom DMSO stocks to a final concentration of 1% DMSO. Concentration ofUDP-Galf [Marlow, A. L. and L. L. Kiessling, Improved Chemical Synthesisof UDP-Galactofuranose. Org Lett, 2001. 3(16): p. 2517-2519] was heldconstant at the Km of the UGM homolog being analyzed, except forgeneration of Lineweaver-Burk plots. Reaction time and substrateconcentration were varied for Lineweaver-Burk analysis, and eachcondition was tested in triplicate. Quenched reactions were run througha CarboPac PA-100 column (Thermo Scientific) on an Agilent 1260 InfinityHPLC using an isocratic elution of 200 mM ammonium acetate (pH 8) toseparate substrate and product peaks.

Small molecule binding to UGM. A fluorescence polarization assay wasused to measure ligand binding to KpUGM [Soltero-Higgin et al. 2004,Carlson et al. 2006] Tumbling of the fluorescein-UDP conjugated probewas measured on a Tecan M1000 microplate reader, exciting with 470 nmlight and monitoring emission at 525 nm. Each condition was tested intriplicate in the presence of 220 nM KpUGM and 23.3 nM of the probe.Data was fit with a one-site binding nonlinear regression in GraphPadPrism 6.

Microbroth dilution assay. A starter culture of M. smegmatis mc²155(ATCC 700084) was grown to saturation at 30° C. in Middlebrook 7H9 Brothwith Albumin Dextrose Catalase (ADC) enrichment and 0.05% Tween 80.Small molecules or DMSO (vehicle control) were added to wells of asterile 96-well plate. Cells were diluted 200× (OD_(600˜0.03)) intofresh 7H9 Middlebrook media with 0.05% Tween 80 and added to the plate,yielding a final DMSO concentration of 1% in each well. After 46 hoursof growth in a 30° C. shaking incubator, cell viability was measuredusing an alamar Blue assay (Invitrogen).

Disk diffusion assay. Saturated starter cultures of E. coli B121(DE3),B. subtilis (OI 1878) [Ying, C. W. and G. W. Ordal, Nucleotide sequenceand expression of cheF, an essential gene for chemotaxis in Bacillussubtilis. J Bacteriol, 1989. 171(3): p. 1-8], and M. smegmatis weregrown, the former two species in LB broth and the later in 7H9Middlebrook media. Cells were diluted to an OD₆₀₀ of 0.2 in fresh mediaand spread (100 μL) onto LB agar plates. Following an hour of incubationat 37° C., sterile cloning disks (3.2 mm diameter, Scienceware)impregnated with 100 nmol of compound or 2 μL of DMSO were placed on thesurface of the inoculated solid media. Cells were incubated at 37° C.overnight. Plates with M. smegmatis were incubated 3 additional days atroom temperature. Zones of inhibition were measured from the outer edgeof the cloning disk to the border of cell growth.

Cytotoxicity assay. Four thousand HEK 293T cells were added to wells ofa sterile 96-well plate in 99 μl DMEM with 10% FBS. The plate wasincubated for 24 hours at 37° C. with 5% CO₂ to allow cells to attach.Cells were then treated with serially diluted small molecules or avehicle control. The final DMSO concentration was 1% in each well. After24 hours of incubation, viability of the treated cells was analyzedusing CellTiter-Glo Luminescent Cell Viability Assay (Promega).Viability readings were normalized to DMSO control wells.

TABLE 1 X-ray Data collection Statistics Wavelength (Å) 1.1 Resolutionrange (Å) 42.2-2.70 (2.80-2.70) Space group P 64 2 2 Unit cell 179.4179.4 145.2 90 90 120 Total reflections 370592 Unique reflections 37906Multiplicity 9.8 (9.8) Completeness (%) 99.2 (98.7) Mean I/sigma(I) 20.0(3.8) Wilson B-factor 73.64 R-sym 0.074 (0.642) R-meas 0.078 (0.677)R-pim 0.025 (0.214) Refinement Statistics Resolution range (Å) 42.2-2.7(2.77-2.70) R-factor 0.1847 (0.2906) R-free (5%) 0.2334 (0.3953) Numberof atoms 6633 macromolecules 6372 ligands 166 water 95 Protein residues772 RMS (bonds) 0.008 RMS (angles) 1.23 Ramachandran favored (%) 95Ramachandran outliers (%) 0.78 Clashscore 11.83 Average B-factor 59.50macromolecules 59.20 ligands 77.35 solvent 48.00

Statistics for the highest-resolution shell are shown in parentheses.

See: Dhindsa and Vaid (1986) Indian J. Chem. Vol. 25B pp 283-287

where R can be —(CH₂)p-CO-Y and Y can include an appropriate protectinggroup See: Vovk, M. et al. (2010) Molecules 15:997-1006

REFERENCES

-   1. Richards, M. R. and T. L. Lowary, Chemistry and Biology of    Galactofuranose-Containing Polysaccharides. ChemBioChem, 2009.    10(12): p. 1920-1938.-   2. Tefsen, B., et al., Galactofuranose in eukaryotes: aspects of    biosynthesis and functional impact. Glycobiology, 2012. 22(4): p.    456-469.-   3. Wesener, D. A., et al., UDP-galactopyranose mutase in nematodes.    Biochemistry, 2013. 52(25): p. 4391-8.-   4. Pan, F., et al., Cell Wall Core Galactofuran Synthesis Is    Essential for Growth of Mycobacteria. J Bacteriol, 2001. 183(13): p.    3991-3998.-   5. Soltero-Higgin, M., et al., A unique catalytic mechanism for    UDP-galactopyranose mutase. Nat Struct Mol Biol, 2004. 11(6): p.    539-543.-   6. Dykhuizen, E. C., et al., Inhibitors of UDP-galactopyranose    mutase thwart mycobacterial growth. J Am Chem Soc, 2008. 130(21): p.    6706-7.-   7. Borrelli, S., et al., Antimycobacterial activity of    UDP-galactopyranose mutase Inhibitors. Int J Antimicrob    Agents, 2010. 36(4): p. 364-8.-   8. Soltero-Higgin, M., et al., Identification of inhibitors for    UDP-galactopyranose Mutase. J Am Chem Soc, 2004. 126(34): p.    10532-3.-   9. Dykhuizen, E. C. and L. L. Kiessling, Potent ligands for    prokaryotic UDP-galactopyranose mutase that exploit an enzyme    subsite. Org Lett, 2009. 11(1): p. 193-6.-   10. Carlson, E. E., J. F. May, and L. L. Kiessling, Chemical probes    of UDP-galactopyranose mutase. Chem Biol, 2006. 13(8): p. 825-37.-   11. Shoichet, B. K., Virtual screening of chemical libraries.    Nature, 2004. 432(7019): p. 862-5.-   12. Ferreira, R. S., et al., Complementarity between a docking and a    High-throughput screen in discovering new cruzain inhibitors. J Med    Chem, 2010. 53(13): p. 4891-905.-   13. Babaoglu, K., et al., Comprehensive mechanistic analysis of hits    from High-throughput and docking screens against beta-lactamase. J    Med Chem, 2008. 51(8): p. 2502-11.-   14. Lorber, D. M. and B. K. Shoichet, Hierarchical docking of    databases of multiple ligand conformations. Curr Top Med Chem, 2005.    5(8): p. 739-49.-   15. Mysinger, M. M. and B. K. Shoichet, Rapid context-dependent    ligand desolvation in molecular docking. J Chem Inf Model, 2010.    50(9): p. 1561-73.-   16. Gruber, T. D., et al., X-ray crystallography reveals a reduced    substrate complex of UDP-galactopyranose mutase poised for covalent    catalysis by flavin. Biochemistry, 2009. 48(39): p. 9171-3.-   17. Mysinger, M. M., et al., Directory of useful decoys, enhanced    (DUD-E): better ligands and decoys for better benchmarking. J Med    Chem, 2012. 55(14): p. 6582-94.-   18. Baell, J. B. and G. A. Holloway, New substructure filters for    removal of pan assay interference compounds (PAINS) from screening    libraries and for their exclusion in bioassays. J Med Chem, 2010.    53(7): p. 2719-40.-   19. Teague, S. J., et al., The Design of Leadlike Combinatorial    Libraries. Angew Chem Int Ed Engl, 1999. 38(24): p. 3743-3748.-   20. Irwin, J. J., et al., ZINC: a free tool to discover chemistry    for biology. J Chem Inf Model, 2012. 52(7): p. 1757-68.-   21. Chad, J. M., et al., Site-directed mutagenesis of    UDP-galactopyranose mutase reveals a critical role for the    active-site, conserved arginine residues. Biochemistry, 2007.    46(23): p. 6723-32.-   22. Lee, R., et al., Enzymatic Synthesis of UDP-Galactofuranose and    an Assay for UDP-Galactopyranose Mutase Based on High-Performance    Liquid Chromatography. Anal Biochem, 1996: p. 1-7.-   23. McGovern, S. L., et al., A common mechanism underlying    promiscuous inhibitors from virtual and high-throughput screening. J    Med Chem, 2002. 45(8): p. 1712-22.-   24. Sanders, D. A. R., et al., UDP-galactopyranose mutase has a    novel structure and Mechanism. Nat Struct Mol Biol, 2001: p. 1-6.-   25. Brenk, R., J. J. Irwin, and B. K. Shoichet, Here be dragons:    docking and screening in an uncharted region of chemical space. J    Biomol Screen, 2005. 10(7): p. 667-74.-   26. Doman, T. N., et al., Molecular docking and high-throughput    screening for novel inhibitors of protein tyrosine phosphatase-1B. J    Med Chem, 2002. 45(11): p. 2213-21.-   27. Wang, Y., et al., PubChem: a public information system for    analyzing bioactivities of small molecules. Nucleic Acids Res, 2009.    37 (Web Server issue): p. W623-33.-   28. Scherman, M. S., et al., Drug targeting Mycobacterium    tuberculosis cell wall synthesis: development of a microtiter    plate-based screen for UDP-galactopyranose mutase and identification    of an inhibitor from a uridine-based Library. Antimicrob Agents    Chemother, 2003. 47(1): p. 378-82.-   29. Gaulton, A., et al., ChEMBL: a large-scale bioactivity database    for drug Discovery. Nucleic Acids Res, 2012. 40 (Database issue): p.    D1100-7.-   30. Owen, S. C., et al., Colloidal aggregation affects the efficacy    of anticancer drugs in cell culture. ACS Chem Biol, 2012. 7(8): p.    1429-35.-   31. Gilson, M. K. and B. Honig, Calculation of the total    electrostatic energy of a macromolecular system: solvation energies,    binding energies, and conformational analysis. Proteins, 1988.    4(1): p. 7-18.-   32. Mysinger, M. M., et al., Structure-based ligand discovery for    the protein-protein interface of chemokine receptor CXCR4. Proc Natl    Acad Sci USA, 2012. 109(14): p. 5517-22.-   33. Davis, I. W. and D. Baker, RosettaLigand docking with full    ligand and receptor Flexibility. J Mol Biol, 2009. 385(2): p.    381-92.-   34. Rogers, D. and M. Hahn, Extended-connectivity fingerprints. J    Chem Inf Model, 2010. 50(5): p. 742-54.-   35. Pilot, P., version 6.1; SciTegic Inc.: San Diego, Calif.    92123-1365.-   36. Gruber, T. D., et al., Ligand Binding and Substrate    Discrimination by UDP-Galactopyranose Mutase. J Mol Biol, 2009.    391(2): p. 327-340.-   37. Beis, K., et al., Crystal Structures of Mycobacteria    tuberculosis and Klebsiella pneumoniae UDP-Galactopyranose Mutase in    the Oxidised State and Klebsiella pneumoniae UDP-Galactopyranose    Mutase in the (Active) Reduced State. J Mol Biol, 2005.348(4): p.    971-982.-   38. Otwinowski, Z. and W. Minor, Processing of x-ray diffraction    data collected in oscillation mode, in Methods in enzymology:    macromolecular crystallography, part A, J. C. W. Carter and R. M.    Sweet, Editors. 1997, Academic Press New York. p. 307-326.-   39. Adams, P. D., et al., PHENIX: a comprehensive Python-based    system for macromolecular structure solution. Acta Crystallogr D    Biol Crystallogr, 2010. 66: p. 213-221.-   40. McCoy, A. J., et al., Phaser crystallographic software. J Appl    Crystallogr, 2007. 40: p. 658-674.-   41. Moriarty, N., R. Grosse-Kunstleve, and P. Adams, Electronic    Ligand Builder and Optimization Workbench (eLBOW): a tool for ligand    coordinate and restraint generation. Acta Crystallogr D Biol    Crystallogr, 2009. 65: p. 1074-1080.-   42. Emsley, P., et al., Features and development of Coot. Acta    Crystallogr D Biol Crystallogr, 2010. 66: p. 486-501.-   43. Afonine, P. V., R. W. Grosse-Kunstleve, and P. D. Adams, The    Phenix refinement Framework. CCP4 Newsl, 2005. 42: p. 8.-   44. Chen, V. B., et al., MolProbity: all-atom structure validation    for macromolecular Crystallography. Acta Crystallogr D Biol    Crystallogr, 2010. 66: p. 12-21.-   45. DeLano, W. L., The PyMOL molecular graphics system. 2002.-   46. Zhang, Q. and H.-w. Liu, Studies of UDP-Galactopyranose Mutase    from Escherichia coli: An Unusual Role of Reduced FAD in Its    Catalysis. Journal of the American Chemical Society, 2000.    122(38): p. 9065-9070.-   47. Marlow, A. L. and L. L. Kiessling, Improved Chemical Synthesis    of UDP-Galactofuranose. Org Lett, 2001. 3(16): p. 2517-2519.-   48. Ying, C. W. and G. W. Ordal, Nucleotide sequence and expression    of cheF, an essential gene for chemotaxis in Bacillus subtilis. J    Bacteriol, 1989. 171(3): p. 1-8.

The invention claimed is:
 1. A method for inhibiting uridine5′-diphosphate-galactopyranose mutase (UGM) which comprises contactingUGM with an amount of one or more compounds of formula I or saltsthereof effective for inhibiting UGM wherein formula I is

where: Y is —OR₃, or —NH₂, R₃ is selected from the group consisting ofhydrogen, an alkyl group, a cycloalkyl group, an alkenyl group, acycloalkenyl group, a heterocyclyl group, an aryl group, and aheteroaryl group, each of which groups is optionally substituted; and R₁and R₂ are independently optionally substituted aryl or heteroarylgroups having one or two rings, where two such rings are linked by asingle bond or are fused, or are alkyl groups substituted with anoptionally substituted aryl, aryloxy, heteroaryl or heteroaryloxy group,wherein the aryl, aryloxy, heteroaryl or heteroaryloxy groups have oneor two rings, where two such rings are linked by a single bond or arefused; where optional substitution is substitution with one or moresubstituents selected from the group consisting of halogen, nitro,cyano, isocyano, thiocyano, isothiocyano, hydroxyl, C₁-C₆ alkyl, C₁-C₆alkoxy, sulfonamide (—SO₂—N(R_(F))₂), azide, sulfonyl (—SO₂—R_(F)),—COOR_(F), —COR_(F), —CON(R_(F))₂, —N(R_(F))₂, and C₁-C₆ haloalkylgroups, where R_(F) is hydrogen or a C₁-C₆ alkyl group.
 2. The method ofclaim 1 wherein the UGM is that of a mycobacterium or a nematode.
 3. Themethod of claim 1 wherein contacting UGM comprises contacting amicroorganism having UGM or contacting the environment of themicroorganism having UGM with the one or more compounds of formula I orsalts thereof.
 4. A method for inhibiting the growth of a microorganismwhich comprises contacting the microorganism or an environmentcontaining the microorganism with an effective amount of one or morecompounds of formula I or salts thereof, wherein formula I is

where: Y is —OR₃, or —NH₂, R₃ is selected from the group consisting ofhydrogen, an alkyl group, a cycloalkyl group, an alkenyl group, acycloalkenyl group, a heterocyclyl group, an aryl group, and aheteroaryl group, each of which groups is optionally substituted; and R₁and R₂ are independently optionally substituted aryl or heteroarylgroups having one or two rings, where two such rings are linked by asingle bond or are fused, or are alkyl groups substituted with anoptionally substituted aryl, aryloxy, heteroaryl or heteroaryloxy group,wherein the aryl, aryloxy, heteroaryl or heteroaryloxy groups have oneor two rings, where two such rings are linked by a single bond or fused;where optional substitution is substitution with one or moresubstituents selected from the group consisting of halogen, nitro,cyano, isocyano, thiocyano, isothiocyano, hydroxyl, C₁-C₆ alkyl, C₁-C₆alkoxy, sulfonamide (—SO₂—N(R_(F))₂), azide, sulfonyl (—SO₂—R_(F)),—COOR_(F), —COR_(F), —CON(R_(F))₂, —N(R_(F))₂, and C₁-C₆ haloalkylgroups, where R_(F) is hydrogen or a C₁-C₆ alkyl group, wherein themicroorganism is a fungus, algae, bacterium or nematode.
 5. The methodof claim 4 wherein the microorganism is a mycobacterium or a nematode.6. A method of treating an infection by a microorganism having UGM in anindividual in need of such treatment by administering to the individualan effective amount of one or more compounds of formula I or saltsthereof, wherein formula I is:

where: Y is —OR₃, or —NH₂, R₃ is selected from the group consisting ofhydrogen, an alkyl group, a cycloalkyl group, an alkenyl group, acycloalkenyl group, a heterocyclyl group, an aryl group, and aheteroaryl group, each of which groups is optionally substituted; and R₁and R₂ are independently optionally substituted aryl or heteroarylgroups having one or two rings, where two such rings are linked by asingle bond or are fused, or are alkyl groups substituted with anoptionally substituted aryl, aryloxy, heteroaryl or heteroaryloxy group,wherein the aryl, aryloxy, heteroaryl or heteroaryloxy groups have oneor two rings, where two such rings are linked by a single bond or fused;where optional substitution is substitution with one or moresubstituents selected from the group consisting of halogen, nitro,cyano, isocyano, thiocyano, isothiocyano, hydroxyl, C₁-C₆ alkyl, C₁-C₆alkoxy, sulfonamide (—SO₂—N(R_(F))₂), azide, sulfonyl (—SO₂—R_(F)),—COOR_(F), —COR_(F) , —CON(R_(F))₂, —N(R_(F))₂, and C₁-C₆ haloalkylgroups, where R_(F) is hydrogen or a C₁-C₆ alkyl group; and wherein theinfection is an infection by a fungus, algae, bacterium or nematode. 7.The method of claim 6 wherein the infection is tuberculosis.
 8. Themethod of claim 7 wherein R₁ is p-bromo-benzyl and R₂ isp-chloro-phenyl.
 9. The method of claim 1 wherein R₁ is p-bromo-benzyland R₂ is p-chloro-phenyl.
 10. The method of claim 1 wherein Y is —OR₃;R₃ is hydrogen, or a C₁-C₆ alkyl group; and R₁ and R₂ are independentlyoptionally substituted aryl groups or are C₁-C₃ alkyl groups substitutedwith an optionally substituted aryl group; where optional substitutionis substitution with one or more substituents selected from the groupconsisting of halogen, nitro, cyano, hydroxyl, C₁-C₆ alkyl, C₁-C₆alkoxy, and C₁-C₆ haloalkyl groups.
 11. The method of claim 10 whereinR₁ and R₂ are independently selected from p-halo-substituted phenylgroups, p-halo-substituted benzyl groups, and thien-2-yl groups.
 12. Themethod of claim 10 wherein Y is —OH, R₁ is p-bromo-benzyl and R₂ isp-chloro-phenyl.
 13. A compound of formula:

or a salt thereof, where: Y is —OR₃; R₃ is selected from the groupconsisting of hydrogen, an alkyl group, a cycloalkyl group, an alkenylgroup, a cycloalkenyl group, a heterocyclyl group, an aryl group, and aheteroaryl group, each of which groups is optionally substituted; and R₁and R₂ are independently-p-halo-substituted phenyl groups,p-halo-substituted benzyl groups, or thien-2-yl groups.
 14. Apharmaceutically acceptable composition which comprises one or morecompounds or salts thereof of claim 13 and a pharmaceutically acceptablecarrier


15. The compound of claim 13 or a salt thereof, wherein R₁ or R₂ isp-I-phenyl or p-I-benzyl.
 16. The compound of claim 13 or a saltthereof, wherein R₁ is -p-Br-benzyl and R₂ is a group other thanp-Cl-phenyl.
 17. A compound of formula:

wherein Y is —NH₂, and R₁ and R₂ are independently optionallysubstituted aryl or heteroaryl groups having one or two rings, where twosuch rings are linked by a single bond or are fused, or are alkyl groupssubstituted with an optionally substituted aryl, aryloxy, heteroaryl orheteroaryloxy group, wherein the aryl, aryloxy, heteroaryl orheteroaryloxy groups have one or two rings, where two such rings arelinked by a single bond or are fused; where optional substitution issubstitution with one or more substituents selected from the groupconsisting of halogen, nitro, cyano, isocyano, thiocyano, isothiocyano,hydroxyl, C₁-C₆ alkyl, C₁-C₆ alkoxy, sulfonamide (—SO₂—N(R_(F))₂),azide, sulfonyl (—SO₂—R_(F)), —COOR_(F), —COR_(F), —CON(R_(F))₂,—N(R_(F))₂, and C₁-C₆ haloalkyl groups, where R_(F) is hydrogen or aC₁-C₆ alkyl group.
 18. The compound of claim 17 wherein R₁ and R₂ areindependently selected from p-halo-substituted phenyl groups, ap-halo-substituted benzyl groups and thien-2-yl groups.
 19. Apharmaceutically acceptable composition which comprises one or morecompounds or salts thereof of claim 17 and a pharmaceutically acceptablecarrier.